DataView.ToTable Metoda
Definice
Důležité
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Přetížení
ToTable(Boolean, String[]) |
Vytvoří a vrátí nový DataTable na základě řádků v existujícím DataViewobjektu . |
ToTable(String) |
Vytvoří a vrátí nový DataTable na základě řádků v existujícím DataViewobjektu . |
ToTable(String, Boolean, String[]) |
Vytvoří a vrátí nový DataTable na základě řádků v existujícím DataViewobjektu . |
ToTable() |
Vytvoří a vrátí nový DataTable na základě řádků v existujícím DataViewobjektu . |
Poznámky
Vrácený DataTable objekt udržuje hodnoty následujících vlastností ze zdroje DataTable: Namespace, Prefix, Locale, a CaseSensitive. Každý sloupec ve výsledném DataTable souboru obsahuje identickou kopii všech odpovídajících vlastností v podkladovém DataTableobjektu .
Instance DataRow ve vrácených DataTable
instancích budou obsahovat hodnoty, které jsou konzistentní se sémantikou CLR. To znamená, že pro všechny datové typy kromě uživatelsky definovaných typů se odpovídající hodnoty sloupců zkopírují podle hodnoty. U datových typů definovaných uživatelem se data sloupce kopírují pomocí odkazu.
ToTable(Boolean, String[])
- Zdroj:
- DataView.cs
- Zdroj:
- DataView.cs
- Zdroj:
- DataView.cs
public:
System::Data::DataTable ^ ToTable(bool distinct, ... cli::array <System::String ^> ^ columnNames);
public System.Data.DataTable ToTable (bool distinct, params string[] columnNames);
member this.ToTable : bool * string[] -> System.Data.DataTable
Public Function ToTable (distinct As Boolean, ParamArray columnNames As String()) As DataTable
Parametry
- distinct
- Boolean
Pokud true
, vrácený DataTable objekt obsahuje řádky, které mají jedinečné hodnoty pro všechny sloupce. Výchozí hodnota je false
.
- columnNames
- String[]
Pole řetězců obsahující seznam názvů sloupců, které se mají zahrnout do vráceného DataTablepole . Obsahuje DataTable zadané sloupce v pořadí, v jakém se zobrazují v tomto poli.
Návraty
Nová DataTable instance, která obsahuje požadované řádky a sloupce.
Příklady
Následující příklad konzolové aplikace vytvoří DataTableobjekt , vyplní objekt daty DataTable , seřadí DataViewa nakonec vytvoří DataTable sloupec se dvěma sloupci omezenými na řádky, ve kterých jsou všechny hodnoty jedinečné.
private static void DemonstrateDataView()
{
// Create a DataTable with three columns.
DataTable table = new DataTable("NewTable");
Console.WriteLine("Original table name: " + table.TableName);
DataColumn column = new DataColumn("ID", typeof(System.Int32));
table.Columns.Add(column);
column = new DataColumn("Category", typeof(System.String));
table.Columns.Add(column);
column = new DataColumn("Product", typeof(System.String));
table.Columns.Add(column);
column = new DataColumn("QuantityInStock", typeof(System.Int32));
table.Columns.Add(column);
// Add some items.
DataRow row = table.NewRow();
row.ItemArray = new object[] { 1, "Fruit", "Apple", 14 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 2, "Fruit", "Orange", 27 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 3, "Bread", "Muffin", 23 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 4, "Fish", "Salmon", 12 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 5, "Fish", "Salmon", 15 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 6, "Bread", "Croissant", 23};
table.Rows.Add(row);
// Mark all rows as "accepted". Not required
// for this particular example.
table.AcceptChanges();
// Print current table values.
PrintTableOrView(table, "Current Values in Table");
DataView view = new DataView(table);
view.Sort = "Category";
PrintTableOrView(view, "Current Values in View");
DataTable newTable = view.ToTable(true, "Category", "QuantityInStock");
PrintTableOrView(newTable, "Table created from sorted DataView");
Console.WriteLine("New table name: " + newTable.TableName);
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
private static void PrintTableOrView(DataView dv, string label)
{
System.IO.StringWriter sw;
string output;
DataTable table = dv.Table;
Console.WriteLine(label);
// Loop through each row in the view.
foreach (DataRowView rowView in dv)
{
sw = new System.IO.StringWriter();
// Loop through each column.
foreach (DataColumn col in table.Columns)
{
// Output the value of each column's data.
sw.Write(rowView[col.ColumnName].ToString() + ", ");
}
output = sw.ToString();
// Trim off the trailing ", ", so the output looks correct.
if (output.Length > 2)
{
output = output.Substring(0, output.Length - 2);
}
// Display the row in the console window.
Console.WriteLine(output);
}
Console.WriteLine();
}
private static void PrintTableOrView(DataTable table, string label)
{
System.IO.StringWriter sw;
string output;
Console.WriteLine(label);
// Loop through each row in the table.
foreach (DataRow row in table.Rows)
{
sw = new System.IO.StringWriter();
// Loop through each column.
foreach (DataColumn col in table.Columns)
{
// Output the value of each column's data.
sw.Write(row[col].ToString() + ", ");
}
output = sw.ToString();
// Trim off the trailing ", ", so the output looks correct.
if (output.Length > 2)
{
output = output.Substring(0, output.Length - 2);
}
// Display the row in the console window.
Console.WriteLine(output);
}
Console.WriteLine();
}
Private Sub DemonstrateDataView()
' Create a DataTable with three columns.
Dim table As New DataTable("NewTable")
Console.WriteLine("Original table name: " & table.TableName)
Dim column As New DataColumn("ID", GetType(System.Int32))
table.Columns.Add(column)
column = New DataColumn("Category", GetType(System.String))
table.Columns.Add(column)
column = New DataColumn("Product", GetType(System.String))
table.Columns.Add(column)
column = New DataColumn("QuantityInStock", GetType(System.Int32))
table.Columns.Add(column)
' Add some items.
Dim row As DataRow = table.NewRow()
row.ItemArray = New Object() {1, "Fruit", "Apple", 14}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {2, "Fruit", "Orange", 27}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {3, "Bread", "Muffin", 23}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {4, "Fish", "Salmon", 12}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {5, "Fish", "Salmon", 15}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {6, "Bread", "Croissant", 23}
table.Rows.Add(row)
' Mark all rows as "accepted". Not required
' for this particular example.
table.AcceptChanges()
' Print current table values.
PrintTableOrView(table, "Current Values in Table")
Dim view As New DataView(table)
view.Sort = "Category"
PrintTableOrView(view, "Current Values in View")
Dim newTable As DataTable = view.ToTable( _
True, "Category", "QuantityInStock")
PrintTableOrView(newTable, "Table created from sorted DataView")
Console.WriteLine("New table name: " & newTable.TableName)
Console.WriteLine("Press any key to continue.")
Console.ReadKey()
End Sub
Private Sub PrintTableOrView(ByVal dv As DataView, ByVal label As String)
Dim sw As System.IO.StringWriter
Dim output As String
Dim table As DataTable = dv.Table
Console.WriteLine(label)
' Loop through each row in the view.
For Each rowView As DataRowView In dv
sw = New System.IO.StringWriter
' Loop through each column.
For Each col As DataColumn In table.Columns
' Output the value of each column's data.
sw.Write(rowView(col.ColumnName).ToString() & ", ")
Next
output = sw.ToString
' Trim off the trailing ", ", so the output looks correct.
If output.Length > 2 Then
output = output.Substring(0, output.Length - 2)
End If
' Display the row in the console window.
Console.WriteLine(output)
Next
Console.WriteLine()
End Sub
Private Sub PrintTableOrView(ByVal table As DataTable, ByVal label As String)
Dim sw As System.IO.StringWriter
Dim output As String
Console.WriteLine(label)
' Loop through each row in the table.
For Each row As DataRow In table.Rows
sw = New System.IO.StringWriter
' Loop through each column.
For Each col As DataColumn In table.Columns
' Output the value of each column's data.
sw.Write(row(col).ToString() & ", ")
Next
output = sw.ToString
' Trim off the trailing ", ", so the output looks correct.
If output.Length > 2 Then
output = output.Substring(0, output.Length - 2)
End If
' Display the row in the console window.
Console.WriteLine(output)
Next
Console.WriteLine()
End Sub
V příkladu se zobrazí následující výstup v okně konzoly:
Original table name: NewTable
Current Values in Table
1, Fruit, Apple, 14
2, Fruit, Orange, 27
3, Bread, Muffin, 23
4, Fish, Salmon, 12
5, Fish, Salmon, 15
6, Bread, Croissant, 23
Current Values in View
3, Bread, Muffin, 23
6, Bread, Croissant, 23
4, Fish, Salmon, 12
5, Fish, Salmon, 15
1, Fruit, Apple, 14
2, Fruit, Orange, 27
Table created from sorted DataView
Bread, 23
Fish, 12
Fish, 15
Fruit, 14
Fruit, 27
New table name: NewTable
Poznámky
Vzhledem k tomu, že tato metoda neumožňuje zadat název výstupu DataTable, její název je stejný jako název zdroje DataTable.
Platí pro
ToTable(String)
- Zdroj:
- DataView.cs
- Zdroj:
- DataView.cs
- Zdroj:
- DataView.cs
public:
System::Data::DataTable ^ ToTable(System::String ^ tableName);
public System.Data.DataTable ToTable (string? tableName);
public System.Data.DataTable ToTable (string tableName);
member this.ToTable : string -> System.Data.DataTable
Public Function ToTable (tableName As String) As DataTable
Parametry
Návraty
Nová DataTable instance, která obsahuje požadované řádky a sloupce.
Příklady
Následující příklad konzolové aplikace vytvoří DataTableobjekt , vyplní objekt daty DataTable
, vytvoří filtrované zobrazení založené na původních datech a nakonec vytvoří DataTable
objekt s novým názvem, který obsahuje filtrované řádky.
private static void DemonstrateDataView()
{
// Create a DataTable with three columns.
DataTable table = new DataTable("NewTable");
Console.WriteLine("Original table name: " + table.TableName);
DataColumn column = new DataColumn("ID", typeof(System.Int32));
table.Columns.Add(column);
column = new DataColumn("Category", typeof(System.String));
table.Columns.Add(column);
column = new DataColumn("Product", typeof(System.String));
table.Columns.Add(column);
column = new DataColumn("QuantityInStock", typeof(System.Int32));
table.Columns.Add(column);
// Add some items.
DataRow row = table.NewRow();
row.ItemArray = new object[] { 1, "Fruit", "Apple", 14 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 2, "Fruit", "Orange", 27 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 3, "Bread", "Muffin", 23 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 4, "Fish", "Salmon", 12 };
table.Rows.Add(row);
// Mark all rows as "accepted". Not really required
// for this particular example.
table.AcceptChanges();
// Print current table values.
PrintTableOrView(table, "Current Values in Table");
DataView view = new DataView(table);
view.RowFilter = "QuantityInStock > 15";
PrintTableOrView(view, "Current Values in View");
DataTable newTable = view.ToTable("FilteredTable");
PrintTableOrView(newTable, "Table created from filtered DataView");
Console.WriteLine("New table name: " + newTable.TableName);
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
private static void PrintTableOrView(DataView dv, string label)
{
System.IO.StringWriter sw;
string output;
DataTable table = dv.Table;
Console.WriteLine(label);
// Loop through each row in the view.
foreach (DataRowView rowView in dv)
{
sw = new System.IO.StringWriter();
// Loop through each column.
foreach (DataColumn col in table.Columns)
{
// Output the value of each column's data.
sw.Write(rowView[col.ColumnName].ToString() + ", ");
}
output = sw.ToString();
// Trim off the trailing ", ", so the output looks correct.
if (output.Length > 2)
{
output = output.Substring(0, output.Length - 2);
}
// Display the row in the console window.
Console.WriteLine(output);
}
Console.WriteLine();
}
private static void PrintTableOrView(DataTable table, string label)
{
System.IO.StringWriter sw;
string output;
Console.WriteLine(label);
// Loop through each row in the table.
foreach (DataRow row in table.Rows)
{
sw = new System.IO.StringWriter();
// Loop through each column.
foreach (DataColumn col in table.Columns)
{
// Output the value of each column's data.
sw.Write(row[col].ToString() + ", ");
}
output = sw.ToString();
// Trim off the trailing ", ", so the output looks correct.
if (output.Length > 2)
{
output = output.Substring(0, output.Length - 2);
}
// Display the row in the console window.
Console.WriteLine(output);
}
Console.WriteLine();
}
Private Sub DemonstrateDataView()
' Create a DataTable with three columns.
Dim table As New DataTable("NewTable")
Console.WriteLine("Original table name: " & table.TableName)
Dim column As New DataColumn("ID", GetType(System.Int32))
table.Columns.Add(column)
column = New DataColumn("Category", GetType(System.String))
table.Columns.Add(column)
column = New DataColumn("Product", GetType(System.String))
table.Columns.Add(column)
column = New DataColumn("QuantityInStock", GetType(System.Int32))
table.Columns.Add(column)
' Add some items.
Dim row As DataRow = table.NewRow()
row.ItemArray = New Object() {1, "Fruit", "Apple", 14}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {2, "Fruit", "Orange", 27}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {3, "Bread", "Muffin", 23}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {4, "Fish", "Salmon", 12}
table.Rows.Add(row)
' Mark all rows as "accepted". Not required
' for this particular example.
table.AcceptChanges()
' Print current table values.
PrintTableOrView(table, "Current Values in Table")
Dim view As New DataView(table)
view.RowFilter = "QuantityInStock > 15"
PrintTableOrView(view, "Current Values in View")
Dim newTable As DataTable = view.ToTable("FilteredTable")
PrintTableOrView(newTable, "Table created from filtered DataView")
Console.WriteLine("New table name: " & newTable.TableName)
Console.WriteLine("Press any key to continue.")
Console.ReadKey()
End Sub
Private Sub PrintTableOrView(ByVal dv As DataView, ByVal label As String)
Dim sw As System.IO.StringWriter
Dim output As String
Dim table As DataTable = dv.Table
Console.WriteLine(label)
' Loop through each row in the view.
For Each rowView As DataRowView In dv
sw = New System.IO.StringWriter
' Loop through each column.
For Each col As DataColumn In table.Columns
' Output the value of each column's data.
sw.Write(rowView(col.ColumnName).ToString() & ", ")
Next
output = sw.ToString
' Trim off the trailing ", ", so the output looks correct.
If output.Length > 2 Then
output = output.Substring(0, output.Length - 2)
End If
' Display the row in the console window.
Console.WriteLine(output)
Next
Console.WriteLine()
End Sub
Private Sub PrintTableOrView(ByVal table As DataTable, ByVal label As String)
Dim sw As System.IO.StringWriter
Dim output As String
Console.WriteLine(label)
' Loop through each row in the table.
For Each row As DataRow In table.Rows
sw = New System.IO.StringWriter
' Loop through each column.
For Each col As DataColumn In table.Columns
' Output the value of each column's data.
sw.Write(row(col).ToString() & ", ")
Next
output = sw.ToString
' Trim off the trailing ", ", so the output looks correct.
If output.Length > 2 Then
output = output.Substring(0, output.Length - 2)
End If
' Display the row in the console window.
Console.WriteLine(output)
Next
Console.WriteLine()
End Sub
V příkladu se v okně konzoly zobrazí následující text:
Original table name: NewTable
Current Values in Table
1, Fruit, Apple, 14
2, Fruit, Orange, 27
3, Bread, Muffin, 23
4, Fish, Salmon, 12
Current Values in View
2, Fruit, Orange, 27
3, Bread, Muffin, 23
Table created from filtered DataView
2, Fruit, Orange, 27
3, Bread, Muffin, 23
New table name: FilteredTable
Poznámky
Vzhledem k tomu, že tato metoda neumožňuje zadat podmnožinu dostupných sloupců, výstupní tabulka obsahuje stejné sloupce jako vstupní tabulka.
Viz také
Platí pro
ToTable(String, Boolean, String[])
- Zdroj:
- DataView.cs
- Zdroj:
- DataView.cs
- Zdroj:
- DataView.cs
public:
System::Data::DataTable ^ ToTable(System::String ^ tableName, bool distinct, ... cli::array <System::String ^> ^ columnNames);
public System.Data.DataTable ToTable (string? tableName, bool distinct, params string[] columnNames);
public System.Data.DataTable ToTable (string tableName, bool distinct, params string[] columnNames);
member this.ToTable : string * bool * string[] -> System.Data.DataTable
Public Function ToTable (tableName As String, distinct As Boolean, ParamArray columnNames As String()) As DataTable
Parametry
- distinct
- Boolean
Pokud true
, vrácený DataTable objekt obsahuje řádky, které mají jedinečné hodnoty pro všechny sloupce. Výchozí hodnota je false
.
- columnNames
- String[]
Pole řetězců obsahující seznam názvů sloupců, které se mají zahrnout do vráceného DataTablepole . Obsahuje DataTable
zadané sloupce v pořadí, v jakém se zobrazují v tomto poli.
Návraty
Nová DataTable instance, která obsahuje požadované řádky a sloupce.
Příklady
Následující příklad konzolové aplikace vytvoří DataTableobjekt , vyplní objekt daty DataTable , seřadí DataViewa nakonec vytvoří DataTable objekt s novým názvem, který obsahuje pouze dva sloupce omezené na řádky, ve kterých jsou všechny hodnoty jedinečné.
private static void DemonstrateDataView()
{
// Create a DataTable with three columns.
DataTable table = new DataTable("NewTable");
Console.WriteLine("Original table name: " + table.TableName);
DataColumn column = new DataColumn("ID", typeof(System.Int32));
table.Columns.Add(column);
column = new DataColumn("Category", typeof(System.String));
table.Columns.Add(column);
column = new DataColumn("Product", typeof(System.String));
table.Columns.Add(column);
column = new DataColumn("QuantityInStock", typeof(System.Int32));
table.Columns.Add(column);
// Add some items.
DataRow row = table.NewRow();
row.ItemArray = new object[] { 1, "Fruit", "Apple", 14 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 2, "Fruit", "Orange", 27 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 3, "Bread", "Muffin", 23 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 4, "Fish", "Salmon", 12 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 5, "Fish", "Salmon", 15 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 6, "Bread", "Croissant", 23};
table.Rows.Add(row);
// Mark all rows as "accepted". Not required
// for this particular example.
table.AcceptChanges();
// Print current table values.
PrintTableOrView(table, "Current Values in Table");
DataView view = new DataView(table);
view.Sort = "Category";
PrintTableOrView(view, "Current Values in View");
DataTable newTable = view.ToTable("UniqueData", true,
"Category", "QuantityInStock");
PrintTableOrView(newTable, "Table created from sorted DataView");
Console.WriteLine("New table name: " + newTable.TableName);
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
private static void PrintTableOrView(DataView dv, string label)
{
System.IO.StringWriter sw;
string output;
DataTable table = dv.Table;
Console.WriteLine(label);
// Loop through each row in the view.
foreach (DataRowView rowView in dv)
{
sw = new System.IO.StringWriter();
// Loop through each column.
foreach (DataColumn col in table.Columns)
{
// Output the value of each column's data.
sw.Write(rowView[col.ColumnName].ToString() + ", ");
}
output = sw.ToString();
// Trim off the trailing ", ", so the output looks correct.
if (output.Length > 2)
{
output = output.Substring(0, output.Length - 2);
}
// Display the row in the console window.
Console.WriteLine(output);
}
Console.WriteLine();
}
private static void PrintTableOrView(DataTable table, string label)
{
System.IO.StringWriter sw;
string output;
Console.WriteLine(label);
// Loop through each row in the table.
foreach (DataRow row in table.Rows)
{
sw = new System.IO.StringWriter();
// Loop through each column.
foreach (DataColumn col in table.Columns)
{
// Output the value of each column's data.
sw.Write(row[col].ToString() + ", ");
}
output = sw.ToString();
// Trim off the trailing ", ", so the output looks correct.
if (output.Length > 2)
{
output = output.Substring(0, output.Length - 2);
}
// Display the row in the console window.
Console.WriteLine(output);
} //
Console.WriteLine();
}
Private Sub DemonstrateDataView()
' Create a DataTable with three columns.
Dim table As New DataTable("NewTable")
Console.WriteLine("Original table name: " & table.TableName)
Dim column As New DataColumn("ID", GetType(System.Int32))
table.Columns.Add(column)
column = New DataColumn("Category", GetType(System.String))
table.Columns.Add(column)
column = New DataColumn("Product", GetType(System.String))
table.Columns.Add(column)
column = New DataColumn("QuantityInStock", GetType(System.Int32))
table.Columns.Add(column)
' Add some items.
Dim row As DataRow = table.NewRow()
row.ItemArray = New Object() {1, "Fruit", "Apple", 14}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {2, "Fruit", "Orange", 27}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {3, "Bread", "Muffin", 23}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {4, "Fish", "Salmon", 12}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {5, "Fish", "Salmon", 15}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {6, "Bread", "Croissant", 23}
table.Rows.Add(row)
' Mark all rows as "accepted". Not required
' for this particular example.
table.AcceptChanges()
' Print current table values.
PrintTableOrView(table, "Current Values in Table")
Dim view As New DataView(table)
view.Sort = "Category"
PrintTableOrView(view, "Current Values in View")
Dim newTable As DataTable = view.ToTable("UniqueData", _
True, "Category", "QuantityInStock")
PrintTableOrView(newTable, "Table created from sorted DataView")
Console.WriteLine("New table name: " & newTable.TableName)
Console.WriteLine("Press any key to continue.")
Console.ReadKey()
End Sub
Private Sub PrintTableOrView(ByVal dv As DataView, ByVal label As String)
Dim sw As System.IO.StringWriter
Dim output As String
Dim table As DataTable = dv.Table
Console.WriteLine(label)
' Loop through each row in the view.
For Each rowView As DataRowView In dv
sw = New System.IO.StringWriter
' Loop through each column.
For Each col As DataColumn In table.Columns
' Output the value of each column's data.
sw.Write(rowView(col.ColumnName).ToString() & ", ")
Next
output = sw.ToString
' Trim off the trailing ", ", so the output looks correct.
If output.Length > 2 Then
output = output.Substring(0, output.Length - 2)
End If
' Display the row in the console window.
Console.WriteLine(output)
Next
Console.WriteLine()
End Sub
Private Sub PrintTableOrView(ByVal table As DataTable, ByVal label As String)
Dim sw As System.IO.StringWriter
Dim output As String
Console.WriteLine(label)
' Loop through each row in the table.
For Each row As DataRow In table.Rows
sw = New System.IO.StringWriter
' Loop through each column.
For Each col As DataColumn In table.Columns
' Output the value of each column's data.
sw.Write(row(col).ToString() & ", ")
Next
output = sw.ToString
' Trim off the trailing ", ", so the output looks correct.
If output.Length > 2 Then
output = output.Substring(0, output.Length - 2)
End If
' Display the row in the console window.
Console.WriteLine(output)
Next
Console.WriteLine()
End Sub
V příkladu se zobrazí následující výstup v okně konzoly:
Original table name: NewTable
Current Values in Table
1, Fruit, Apple, 14
2, Fruit, Orange, 27
3, Bread, Muffin, 23
4, Fish, Salmon, 12
5, Fish, Salmon, 15
6, Bread, Croissant, 23
Current Values in View
3, Bread, Muffin, 23
6, Bread, Croissant, 23
4, Fish, Salmon, 12
5, Fish, Salmon, 15
1, Fruit, Apple, 14
2, Fruit, Orange, 27
Table created from sorted DataView
Bread, 23
Fish, 12
Fish, 15
Fruit, 14
Fruit, 27
New table name: UniqueData
Poznámky
Tuto přetíženou verzi ToTable metody použijte, pokud potřebujete načíst jedinečné hodnoty v podmnožině dostupných sloupců a zadat nový název pro vrácenou DataTablehodnotu . Pokud nepotřebujete jedinečné řádky nebo podmnožinu sloupců, přečtěte si téma ToTable.
Viz také
Platí pro
ToTable()
- Zdroj:
- DataView.cs
- Zdroj:
- DataView.cs
- Zdroj:
- DataView.cs
public:
System::Data::DataTable ^ ToTable();
public System.Data.DataTable ToTable ();
member this.ToTable : unit -> System.Data.DataTable
Public Function ToTable () As DataTable
Návraty
Nová DataTable instance, která obsahuje požadované řádky a sloupce.
Příklady
Následující příklad konzolové aplikace vytvoří DataTable, vyplní objekt daty DataTable , vytvoří filtrované zobrazení založené na původních datech a nakonec vytvoří DataTable , který obsahuje filtrované řádky.
using System;
using System.Data;
class Program {
static void Main() {
DemonstrateDataView();
}
private static void DemonstrateDataView() {
// Create a DataTable with three columns.
DataTable table = new DataTable("NewTable");
Console.WriteLine("Original table name: " + table.TableName);
DataColumn column = new DataColumn("ID", typeof(System.Int32));
table.Columns.Add(column);
column = new DataColumn("Category", typeof(System.String));
table.Columns.Add(column);
column = new DataColumn("Product", typeof(System.String));
table.Columns.Add(column);
column = new DataColumn("QuantityInStock", typeof(System.Int32));
table.Columns.Add(column);
// Add some items.
DataRow row = table.NewRow();
row.ItemArray = new object[] { 1, "Fruit", "Apple", 14 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 2, "Fruit", "Orange", 27 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 3, "Bread", "Muffin", 23 };
table.Rows.Add(row);
row = table.NewRow();
row.ItemArray = new object[] { 4, "Fish", "Salmon", 12 };
table.Rows.Add(row);
// Mark all rows as "accepted". Not really required
// for this particular example.
table.AcceptChanges();
// Print current table values.
PrintTableOrView(table, "Current Values in Table");
DataView view = new DataView(table);
view.RowFilter = "QuantityInStock > 15";
PrintTableOrView(view, "Current Values in View");
DataTable newTable = view.ToTable();
PrintTableOrView(newTable, "Table created from filtered DataView");
Console.WriteLine("New table name: " + newTable.TableName);
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
private static void PrintTableOrView(DataView dv, string label) {
System.IO.StringWriter sw;
string output;
DataTable table = dv.Table;
Console.WriteLine(label);
// Loop through each row in the view.
foreach (DataRowView rowView in dv) {
sw = new System.IO.StringWriter();
// Loop through each column.
foreach (DataColumn col in table.Columns) {
// Output the value of each column's data.
sw.Write(rowView[col.ColumnName].ToString() + ", ");
}
output = sw.ToString();
// Trim off the trailing ", ", so the output looks correct.
if (output.Length > 2)
output = output.Substring(0, output.Length - 2);
// Display the row in the console window.
Console.WriteLine(output);
}
Console.WriteLine();
}
private static void PrintTableOrView(DataTable table, string label) {
System.IO.StringWriter sw;
string output;
Console.WriteLine(label);
// Loop through each row in the table.
foreach (DataRow row in table.Rows) {
sw = new System.IO.StringWriter();
// Loop through each column.
foreach (DataColumn col in table.Columns) {
// Output the value of each column's data.
sw.Write(row[col].ToString() + ", ");
}
output = sw.ToString();
// Trim off the trailing ", ", so the output looks correct.
if (output.Length > 2)
output = output.Substring(0, output.Length - 2);
// Display the row in the console window.
Console.WriteLine(output);
}
Console.WriteLine();
}
}
Private Sub DemonstrateDataView()
' Create a DataTable with three columns.
Dim table As New DataTable("NewTable")
Console.WriteLine("Original table name: " & table.TableName)
Dim column As New DataColumn("ID", GetType(System.Int32))
table.Columns.Add(column)
column = New DataColumn("Category", GetType(System.String))
table.Columns.Add(column)
column = New DataColumn("Product", GetType(System.String))
table.Columns.Add(column)
column = New DataColumn("QuantityInStock", GetType(System.Int32))
table.Columns.Add(column)
' Add some items.
Dim row As DataRow = table.NewRow()
row.ItemArray = New Object() {1, "Fruit", "Apple", 14}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {2, "Fruit", "Orange", 27}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {3, "Bread", "Muffin", 23}
table.Rows.Add(row)
row = table.NewRow()
row.ItemArray = New Object() {4, "Fish", "Salmon", 12}
table.Rows.Add(row)
' Mark all rows as "accepted". Not required
' for this particular example.
table.AcceptChanges()
' Print current table values.
PrintTableOrView(table, "Current Values in Table")
Dim view As New DataView(table)
view.RowFilter = "QuantityInStock > 15"
PrintTableOrView(view, "Current Values in View")
Dim newTable As DataTable = view.ToTable()
PrintTableOrView(newTable, "Table created from filtered DataView")
Console.WriteLine("New table name: " & newTable.TableName)
Console.WriteLine("Press any key to continue.")
Console.ReadKey()
End Sub
Private Sub PrintTableOrView(ByVal dv As DataView, ByVal label As String)
Dim sw As System.IO.StringWriter
Dim output As String
Dim table As DataTable = dv.Table
Console.WriteLine(label)
' Loop through each row in the view.
For Each rowView As DataRowView In dv
sw = New System.IO.StringWriter
' Loop through each column.
For Each col As DataColumn In table.Columns
' Output the value of each column's data.
sw.Write(rowView(col.ColumnName).ToString() & ", ")
Next
output = sw.ToString
' Trim off the trailing ", ", so the output looks correct.
If output.Length > 2 Then
output = output.Substring(0, output.Length - 2)
End If
' Display the row in the console window.
Console.WriteLine(output)
Next
Console.WriteLine()
End Sub
Private Sub PrintTableOrView(ByVal table As DataTable, ByVal label As String)
Dim sw As System.IO.StringWriter
Dim output As String
Console.WriteLine(label)
' Loop through each row in the table.
For Each row As DataRow In table.Rows
sw = New System.IO.StringWriter
' Loop through each column.
For Each col As DataColumn In table.Columns
' Output the value of each column's data.
sw.Write(row(col).ToString() & ", ")
Next
output = sw.ToString
' Trim off the trailing ", ", so the output looks correct.
If output.Length > 2 Then
output = output.Substring(0, output.Length - 2)
End If
' Display the row in the console window.
Console.WriteLine(output)
Next
Console.WriteLine()
End Sub
V příkladu se v okně konzoly zobrazí následující text:
Original table name: NewTable
Current Values in Table
1, Fruit, Apple, 14
2, Fruit, Orange, 27
3, Bread, Muffin, 23
4, Fish, Salmon, 12
Current Values in View
2, Fruit, Orange, 27
3, Bread, Muffin, 23
Table created from filtered DataView
2, Fruit, Orange, 27
3, Bread, Muffin, 23
New table name: NewTable
Poznámky
Vzhledem k tomu, že tato metoda neumožňuje zadat název výstupu DataTable, její název je stejný jako název zdroje DataTable
. Vzhledem k tomu, že tato metoda neumožňuje zadat podmnožinu dostupných sloupců, výstupní tabulka obsahuje stejné sloupce jako vstupní tabulka.