DataSet.Load Method

Reference

Definition

Namespace:: System.Data

Assembly:: System.Data.Common.dll

Assembly:: System.Data.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Fills a DataSet with values from a data source using the supplied IDataReader.

Overloads

Load(IDataReader, LoadOption, DataTable[])	Fills a DataSet with values from a data source using the supplied IDataReader, using an array of DataTable instances to supply the schema and namespace information.
Load(IDataReader, LoadOption, String[])	Fills a DataSet with values from a data source using the supplied IDataReader, using an array of strings to supply the names for the tables within the `DataSet`.
Load(IDataReader, LoadOption, FillErrorEventHandler, DataTable[])	Fills a DataSet with values from a data source using the supplied IDataReader, using an array of DataTable instances to supply the schema and namespace information.

Remarks

The Load method provides a technique for filling a single DataTable with data, retrieved from an IDataReader instance. This method provides the same functionality, but allows you to load multiple result sets from an IDataReader into multiple tables within a DataSet.

If the DataSet already contains rows, the incoming data from the data source is merged with the existing rows.

The Load method can be used in several common scenarios, all centered around getting data from a specified data source and adding it to the current data container (in this case, a DataSet). These scenarios describe standard usage for a DataSet, describing its update and merge behavior.

A DataSet synchronizes or updates with a single primary data source. The DataSet tracks changes, allowing synchronization with the primary data source. In addition, a DataSet can accept incremental data from one or more secondary data sources. The DataSet isn't responsible for tracking changes in order to allow synchronization with the secondary data source.

Given these two hypothetical data sources, a user is likely to require one of the following behaviors:

Initialize DataSet from a primary data source. In this scenario, the user wants to initialize an empty DataSet with values from the primary data source. One or more DataTable's contents are modified. Later the user intends to propagate changes back to the primary data source.
Preserve changes and re-synchronize from the primary data source. In this scenario, the user wants to take the DataSet filled in the previous scenario and perform an incremental synchronization with the primary data source, preserving modifications made in the DataSet.
Incremental data feed from secondary data sources. In this scenario, the user wants to merge changes from one or more secondary data sources, and propagate those changes back to the primary data source.

The Load method makes all these scenarios possible. This method allows you to specify a load option parameter, indicating how rows already in a DataTable combine with rows being loaded. The following table describes the three load options provided by the LoadOption enumeration. In each case, the description indicates the behavior when the primary key of a row in the incoming data matches the primary key of an existing row.

Load Option	Description
`PreserveChanges` (default)	Updates the original version of the row with the value of the incoming row.
`OverwriteChanges`	Updates the current and original versions of the row with the value of the incoming row.
`Upsert`	Updates the current version of the row with the value of the incoming row.

In general, the PreserveChanges and OverwriteChanges options are intended for scenarios in which the user needs to synchronize the DataSet and its changes with the primary data source. The Upsert option facilitates aggregating changes from one or more secondary data sources.

Load(IDataReader, LoadOption, DataTable[])

Source:: DataSet.cs

Source:: DataSet.cs

Source:: DataSet.cs

Fills a DataSet with values from a data source using the supplied IDataReader, using an array of DataTable instances to supply the schema and namespace information.

public:
 void Load(System::Data::IDataReader ^ reader, System::Data::LoadOption loadOption, ... cli::array <System::Data::DataTable ^> ^ tables);

public void Load (System.Data.IDataReader reader, System.Data.LoadOption loadOption, params System.Data.DataTable[] tables);

member this.Load : System.Data.IDataReader * System.Data.LoadOption * System.Data.DataTable[] -> unit

Public Sub Load (reader As IDataReader, loadOption As LoadOption, ParamArray tables As DataTable())

Parameters

reader: IDataReader

An IDataReader that provides one or more result sets.

loadOption: LoadOption

A value from the LoadOption enumeration that indicates how rows already in the DataTable instances within the DataSet will be combined with incoming rows that share the same primary key.

tables: DataTable[]

An array of DataTable instances, from which the Load(IDataReader, LoadOption, DataTable[]) method retrieves name and namespace information. Each of these tables must be a member of the DataTableCollection contained by this DataSet.

Examples

The following example creates a new DataSet, adds two DataTable instances to the DataSet, and then fills the DataSet using the Load method, retrieving data from a DataTableReader that contains two result sets. Finally, the example displays the contents of the tables in the console window.

static void Main()
{
    DataSet dataSet = new DataSet();

    DataTable customerTable = new DataTable();
    DataTable productTable = new DataTable();

    // This information is cosmetic, only.
    customerTable.TableName = "Customers";
    productTable.TableName = "Products";

    // Add the tables to the DataSet:
    dataSet.Tables.Add(customerTable);
    dataSet.Tables.Add(productTable);

    // Load the data into the existing DataSet.
    DataTableReader reader = GetReader();
    dataSet.Load(reader, LoadOption.OverwriteChanges,
        customerTable, productTable);

    // Print out the contents of each table:
    foreach (DataTable table in dataSet.Tables)
    {
        PrintColumns(table);
    }

    Console.WriteLine("Press any key to continue.");
    Console.ReadKey();
}

private static DataTable GetCustomers()
{
    // Create sample Customers table.
    DataTable table = new DataTable();
    table.TableName = "Customers";

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(string));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 0, "Mary" });
    table.Rows.Add(new object[] { 1, "Andy" });
    table.Rows.Add(new object[] { 2, "Peter" });
    table.AcceptChanges();
    return table;
}

private static DataTable GetProducts()
{
    // Create sample Products table.
    DataTable table = new DataTable();
    table.TableName = "Products";

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID",
        typeof(int));
    table.Columns.Add("Name", typeof(string));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 0, "Wireless Network Card" });
    table.Rows.Add(new object[] { 1, "Hard Drive" });
    table.Rows.Add(new object[] { 2, "Monitor" });
    table.Rows.Add(new object[] { 3, "CPU" });
    table.AcceptChanges();
    return table;
}

private static void PrintColumns(DataTable table)
{
    Console.WriteLine();
    Console.WriteLine(table.TableName);
    Console.WriteLine("=========================");
    // Loop through all the rows in the table:
    foreach (DataRow row in table.Rows)
    {
        for (int i = 0; i < table.Columns.Count; i++)
        {
            Console.Write(row[i] + " ");
        }
        Console.WriteLine();
    }
}

private static DataTableReader GetReader()
{
    // Return a DataTableReader containing multiple
    // result sets, just for the sake of this demo.
    DataSet dataSet = new DataSet();
    dataSet.Tables.Add(GetCustomers());
    dataSet.Tables.Add(GetProducts());
    return dataSet.CreateDataReader();
}

Sub Main()
    Dim dataSet As New DataSet

    Dim customerTable As New DataTable
    Dim productTable As New DataTable

    ' This information is cosmetic, only.
    customerTable.TableName = "Customers"
    productTable.TableName = "Products"

    ' Add the tables to the DataSet:
    dataSet.Tables.Add(customerTable)
    dataSet.Tables.Add(productTable)

    ' Load the data into the existing DataSet. 
    Dim reader As DataTableReader = GetReader()
    dataSet.Load(reader, LoadOption.OverwriteChanges, _
        customerTable, productTable)

    ' Print out the contents of each table:
    For Each table As DataTable In dataSet.Tables
        PrintColumns(table)
    Next

    Console.WriteLine("Press any key to continue.")
    Console.ReadKey()
End Sub

Private Function GetCustomers() As DataTable
    ' Create sample Customers table.
    Dim table As New DataTable
    table.TableName = "Customers"

    ' Create two columns, ID and Name.
    Dim idColumn As DataColumn = table.Columns.Add("ID", _
        GetType(Integer))
    table.Columns.Add("Name", GetType(String))

    ' Set the ID column as the primary key column.
    table.PrimaryKey = New DataColumn() {idColumn}

    table.Rows.Add(New Object() {0, "Mary"})
    table.Rows.Add(New Object() {1, "Andy"})
    table.Rows.Add(New Object() {2, "Peter"})
    table.AcceptChanges()
    Return table
End Function

Private Function GetProducts() As DataTable
    ' Create sample Products table, in order
    ' to demonstrate the behavior of the DataTableReader.
    Dim table As New DataTable
    table.TableName = "Products"

    ' Create two columns, ID and Name.
    Dim idColumn As DataColumn = table.Columns.Add("ID", _
        GetType(Integer))
    table.Columns.Add("Name", GetType(String))

    ' Set the ID column as the primary key column.
    table.PrimaryKey = New DataColumn() {idColumn}

    table.Rows.Add(New Object() {0, "Wireless Network Card"})
    table.Rows.Add(New Object() {1, "Hard Drive"})
    table.Rows.Add(New Object() {2, "Monitor"})
    table.Rows.Add(New Object() {3, "CPU"})
    Return table
End Function

Private Function GetReader() As DataTableReader
    ' Return a DataTableReader containing multiple
    ' result sets, just for the sake of this demo.
    Dim dataSet As New DataSet
    dataSet.Tables.Add(GetCustomers())
    dataSet.Tables.Add(GetProducts())
    Return dataSet.CreateDataReader()
End Function

Private Sub PrintColumns( _
   ByVal table As DataTable)

    Console.WriteLine()
    Console.WriteLine(table.TableName)
    Console.WriteLine("=========================")
    ' Loop through all the rows in the table.
    For Each row As DataRow In table.Rows
        For Each col As DataColumn In table.Columns
            Console.Write(row(col).ToString() & " ")
        Next
        Console.WriteLine()
    Next
End Sub

Remarks

Note

The load operation will fail with an InvalidOperationException if any of the source data columns in the incoming reader are computed columns.

The loadOption parameter allows you to specify how you want the imported data to interact with existing data, and can be any of the values from the LoadOption enumeration. See the documentation for the DataTable Load method for more information on using this parameter.

The tables parameter allows you to specify an array of DataTable instances, indicating the order of the tables corresponding to each result set loaded from the reader. The Load method fills each supplied DataTable instance with data from a single result set from the source data reader. After each result set, the Load method moves on to the next result set within the reader, until there are no more result sets.

The name resolution scheme for this method is the same as that followed by the Fill method of the DbDataAdapter class.

Applies to

Load(IDataReader, LoadOption, String[])

Source:: DataSet.cs

Source:: DataSet.cs

Source:: DataSet.cs

Fills a DataSet with values from a data source using the supplied IDataReader, using an array of strings to supply the names for the tables within the DataSet.

public:
 void Load(System::Data::IDataReader ^ reader, System::Data::LoadOption loadOption, ... cli::array <System::String ^> ^ tables);

public void Load (System.Data.IDataReader reader, System.Data.LoadOption loadOption, params string[] tables);

member this.Load : System.Data.IDataReader * System.Data.LoadOption * string[] -> unit

Public Sub Load (reader As IDataReader, loadOption As LoadOption, ParamArray tables As String())

Parameters

reader: IDataReader

An IDataReader that provides one or more result sets.

loadOption: LoadOption

A value from the LoadOption enumeration that indicates how rows already in the DataTable instances within the DataSet will be combined with incoming rows that share the same primary key.

tables: String[]

An array of strings, from which the Load method retrieves table name information.

Examples

The following Console application example first creates tables and loads data from a reader into a DataSet, using the Load method. The example then adds tables to a DataSet and attempts to fill the tables with data from a DataTableReader. In this example, because the parameters passed to the Load method indicate a table name that does not exist, the Load method creates a new table to match the name passed as a parameter. Once the data has been loaded, the example displays the contents of all its tables in the Console window.

static void Main()
{
    DataSet dataSet = new DataSet();

    DataTableReader reader = GetReader();

    // The tables listed as parameters for the Load method
    // should be in the same order as the tables within the IDataReader.
    dataSet.Load(reader, LoadOption.Upsert, "Customers", "Products");
    foreach (DataTable table in dataSet.Tables)
    {
        PrintColumns(table);
    }

    // Now try the example with the DataSet
    // already filled with data:
    dataSet = new DataSet();
    dataSet.Tables.Add(GetCustomers());
    dataSet.Tables.Add(GetProducts());

    // Retrieve a data reader containing changed data:
    reader = GetReader();

    // Load the data into the existing DataSet. Retrieve the order of the
    // the data in the reader from the
    // list of table names in the parameters. If you specify
    // a new table name here, the Load method will create
    // a corresponding new table.
    dataSet.Load(reader, LoadOption.Upsert,
        "NewCustomers", "Products");
    foreach (DataTable table in dataSet.Tables)
    {
        PrintColumns(table);
    }

    Console.WriteLine("Press any key to continue.");
    Console.ReadKey();
}

private static DataTable GetCustomers()
{
    // Create sample Customers table.
    DataTable table = new DataTable();
    table.TableName = "Customers";

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(string));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 0, "Mary" });
    table.Rows.Add(new object[] { 1, "Andy" });
    table.Rows.Add(new object[] { 2, "Peter" });
    table.AcceptChanges();
    return table;
}

private static DataTable GetProducts()
{
    // Create sample Products table.
    DataTable table = new DataTable();
    table.TableName = "Products";

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(string));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 0, "Wireless Network Card" });
    table.Rows.Add(new object[] { 1, "Hard Drive" });
    table.Rows.Add(new object[] { 2, "Monitor" });
    table.Rows.Add(new object[] { 3, "CPU" });
    table.AcceptChanges();
    return table;
}

private static void PrintColumns(DataTable table)
{
    Console.WriteLine();
    Console.WriteLine(table.TableName);
    Console.WriteLine("=========================");
    // Loop through all the rows in the table:
    foreach (DataRow row in table.Rows)
    {
        for (int i = 0; i < table.Columns.Count; i++)
        {
            Console.Write(row[i] + " ");
        }
        Console.WriteLine();
    }
}

private static DataTableReader GetReader()
{
    // Return a DataTableReader containing multiple
    // result sets, just for the sake of this demo.
    DataSet dataSet = new DataSet();
    dataSet.Tables.Add(GetCustomers());
    dataSet.Tables.Add(GetProducts());
    return dataSet.CreateDataReader();
}

Sub Main()
  Dim dataSet As New DataSet
  Dim table As DataTable

  Dim reader As DataTableReader = GetReader()

  ' The tables listed as parameters for the Load method 
  ' should be in the same order as the tables within the IDataReader.
  dataSet.Load(reader, LoadOption.Upsert, "Customers", "Products")
  For Each table In dataSet.Tables
    PrintColumns(table)
  Next

  ' Now try the example with the DataSet
  ' already filled with data:
  dataSet = New DataSet
  dataSet.Tables.Add(GetCustomers())
  dataSet.Tables.Add(GetProducts())

  ' Retrieve a data reader containing changed data:
  reader = GetReader()

  ' Load the data into the existing DataSet. Retrieve the order of the
  ' the data in the reader from the
  ' list of table names in the parameters. If you specify
  ' a new table name here, the Load method will create
  ' a corresponding new table.
  dataSet.Load(reader, LoadOption.Upsert, "NewCustomers", "Products")
  For Each table In dataSet.Tables
    PrintColumns(table)
  Next

  Console.WriteLine("Press any key to continue.")
  Console.ReadKey()
End Sub

Private Function GetCustomers() As DataTable
  ' Create sample Customers table.
  Dim table As New DataTable
  table.TableName = "Customers"

  ' Create two columns, ID and Name.
  Dim idColumn As DataColumn = table.Columns.Add("ID", GetType(Integer))
  table.Columns.Add("Name", GetType(String))

  ' Set the ID column as the primary key column.
  table.PrimaryKey = New DataColumn() {idColumn}

  table.Rows.Add(New Object() {0, "Mary"})
  table.Rows.Add(New Object() {1, "Andy"})
  table.Rows.Add(New Object() {2, "Peter"})
  table.AcceptChanges()
  Return table
End Function

Private Function GetProducts() As DataTable
  ' Create sample Products table, in order
  ' to demonstrate the behavior of the DataTableReader.
  Dim table As New DataTable
  table.TableName = "Products"

  ' Create two columns, ID and Name.
  Dim idColumn As DataColumn = table.Columns.Add("ID", GetType(Integer))
  table.Columns.Add("Name", GetType(String))

  ' Set the ID column as the primary key column.
  table.PrimaryKey = New DataColumn() {idColumn}

  table.Rows.Add(New Object() {0, "Wireless Network Card"})
  table.Rows.Add(New Object() {1, "Hard Drive"})
  table.Rows.Add(New Object() {2, "Monitor"})
  table.Rows.Add(New Object() {3, "CPU"})
  Return table
End Function

Private Function GetReader() As DataTableReader
  ' Return a DataTableReader containing multiple
  ' result sets, just for the sake of this demo.
  Dim dataSet As New DataSet
  dataSet.Tables.Add(GetCustomers())
  dataSet.Tables.Add(GetProducts())
  Return dataSet.CreateDataReader()
End Function

Private Sub PrintColumns( _
   ByVal table As DataTable)

  Console.WriteLine()
  Console.WriteLine(table.TableName)
  Console.WriteLine("=========================")
  ' Loop through all the rows in the table.
  For Each row As DataRow In table.Rows
    For Each col As DataColumn In table.Columns
      Console.Write(row(col).ToString() & " ")
    Next
    Console.WriteLine()
  Next
End Sub

Remarks

Note

The load operation will fail with an InvalidOperationException if any of the source data columns in the incoming reader are computed columns.

The loadOption parameter allows you to specify how you want the imported data to interact with existing data, and can be any of the values from the LoadOption enumeration. See the documentation for the Load method for more information on using this parameter.

The tables parameter allows you to specify an array of table names, indicating the order of the tables corresponding to each result set loaded from the reader. The Load method attempts to find a table within the DataSet matching the name found in the array of table names, in order. If a matching table is found, that table is loaded with the content of the current result set. If no matching table is found, a table is created using the name supplied in the array of table names, and the new table's schema is inferred from the result set. After each result set, the Load method moves on to the next result set within the reader, until there are no more result sets.

The default namespace associated with DataSet, if any, is associated with each newly created DataTable. The name resolution scheme for this method is the same as that followed by the Fill method of the DbDataAdapter class.

Applies to

Load(IDataReader, LoadOption, FillErrorEventHandler, DataTable[])

Source:: DataSet.cs

Source:: DataSet.cs

Source:: DataSet.cs

Fills a DataSet with values from a data source using the supplied IDataReader, using an array of DataTable instances to supply the schema and namespace information.

public:
 virtual void Load(System::Data::IDataReader ^ reader, System::Data::LoadOption loadOption, System::Data::FillErrorEventHandler ^ errorHandler, ... cli::array <System::Data::DataTable ^> ^ tables);

public virtual void Load (System.Data.IDataReader reader, System.Data.LoadOption loadOption, System.Data.FillErrorEventHandler? errorHandler, params System.Data.DataTable[] tables);

public virtual void Load (System.Data.IDataReader reader, System.Data.LoadOption loadOption, System.Data.FillErrorEventHandler errorHandler, params System.Data.DataTable[] tables);

abstract member Load : System.Data.IDataReader * System.Data.LoadOption * System.Data.FillErrorEventHandler * System.Data.DataTable[] -> unit
override this.Load : System.Data.IDataReader * System.Data.LoadOption * System.Data.FillErrorEventHandler * System.Data.DataTable[] -> unit

Public Overridable Sub Load (reader As IDataReader, loadOption As LoadOption, errorHandler As FillErrorEventHandler, ParamArray tables As DataTable())

Parameters

reader: IDataReader

An IDataReader that provides one or more result sets.

loadOption: LoadOption

A value from the LoadOption enumeration that indicates how rows already in the DataTable instances within the DataSet will be combined with incoming rows that share the same primary key.

errorHandler: FillErrorEventHandler

A FillErrorEventHandler delegate to call when an error occurs while loading data.

tables: DataTable[]

An array of DataTable instances, from which the Load(IDataReader, LoadOption, FillErrorEventHandler, DataTable[]) method retrieves name and namespace information.

Examples

The following example adds a table to a DataSet, and then attempts to use the Load method to load data from a DataTableReader that contains an incompatible schema. Rather than trapping the error, this example uses a FillErrorEventHandler delegate to investigate and handle the error. The output is displayed in the console window.

static void Main()
{
    // Attempt to load data from a data reader in which
    // the schema is incompatible with the current schema.
    // If you use exception handling, you won't get the chance
    // to examine each row, and each individual table,
    // as the Load method progresses.
    // By taking advantage of the FillErrorEventHandler delegate,
    // you can interact with the Load process as an error occurs,
    // attempting to fix the problem, or simply continuing or quitting
    // the Load process.:
    DataSet dataSet = new DataSet();
    DataTable table = GetIntegerTable();
    dataSet.Tables.Add(table);
    DataTableReader reader = new DataTableReader(GetStringTable());
    dataSet.Load(reader, LoadOption.OverwriteChanges,
        FillErrorHandler, table);

    Console.WriteLine("Press any key to continue.");
    Console.ReadKey();
}

private static DataTable GetIntegerTable()
{
    // Create sample Customers table, in order
    // to demonstrate the behavior of the DataTableReader.
    DataTable table = new DataTable();

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 4 });
    table.Rows.Add(new object[] { 5 });
    table.AcceptChanges();
    return table;
}

private static DataTable GetStringTable()
{
    // Create sample Customers table, in order
    // to demonstrate the behavior of the DataTableReader.
    DataTable table = new DataTable();

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(string));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { "Mary" });
    table.Rows.Add(new object[] { "Andy" });
    table.Rows.Add(new object[] { "Peter" });
    table.AcceptChanges();
    return table;
}

static void FillErrorHandler(object sender, FillErrorEventArgs e)
{
    // You can use the e.Errors value to determine exactly what
    // went wrong.
    if (e.Errors.GetType() == typeof(System.FormatException))
    {
        Console.WriteLine("Error when attempting to update the value: {0}",
            e.Values[0]);
    }

    // Setting e.Continue to True tells the Load
    // method to continue trying. Setting it to False
    // indicates that an error has occurred, and the
    // Load method raises the exception that got
    // you here.
    e.Continue = true;
}

Sub Main()
  Dim dataSet As New DataSet
  Dim table As New DataTable()

  ' Attempt to load data from a data reader in which
  ' the schema is incompatible with the current schema.
  ' If you use exception handling, you won't get the chance
  ' to examine each row, and each individual table,
  ' as the Load method progresses.
  ' By taking advantage of the FillErrorEventHandler delegate,
  ' you can interact with the Load process as an error occurs,
  ' attempting to fix the problem, or simply continuing or quitting
  ' the Load process.:
  dataSet = New DataSet()
  table = GetIntegerTable()
  dataSet.Tables.Add(table)
  Dim reader As New DataTableReader(GetStringTable())
  dataSet.Load(reader, LoadOption.OverwriteChanges, _
      AddressOf FillErrorHandler, table)

  Console.WriteLine("Press any key to continue.")
  Console.ReadKey()
End Sub

Private Sub FillErrorHandler(ByVal sender As Object, _
  ByVal e As FillErrorEventArgs)
  ' You can use the e.Errors value to determine exactly what
  ' went wrong.
  If e.Errors.GetType Is GetType(System.FormatException) Then
    Console.WriteLine("Error when attempting to update the value: {0}", _
      e.Values(0))
  End If

  ' Setting e.Continue to True tells the Load
  ' method to continue trying. Setting it to False
  ' indicates that an error has occurred, and the 
  ' Load method raises the exception that got 
  ' you here.
  e.Continue = True
End Sub

Private Function GetIntegerTable() As DataTable
  ' Create sample table with a single Int32 column.
  Dim table As New DataTable

  Dim idColumn As DataColumn = table.Columns.Add("ID", _
      GetType(Integer))

  ' Set the ID column as the primary key column.
  table.PrimaryKey = New DataColumn() {idColumn}

  table.Rows.Add(New Object() {4})
  table.Rows.Add(New Object() {5})
  table.TableName = "IntegerTable"
  table.AcceptChanges()
  Return table
End Function

Private Function GetStringTable() As DataTable
  ' Create sample table with a single String column.
  Dim table As New DataTable

  Dim idColumn As DataColumn = table.Columns.Add("ID", _
      GetType(String))

  ' Set the ID column as the primary key column.
  table.PrimaryKey = New DataColumn() {idColumn}

  table.Rows.Add(New Object() {"Mary"})
  table.Rows.Add(New Object() {"Andy"})
  table.Rows.Add(New Object() {"Peter"})
  table.AcceptChanges()
  Return table
End Function

Private Sub PrintColumns( _
   ByVal table As DataTable)

  ' Loop through all the rows in the DataTableReader.
  For Each row As DataRow In table.Rows
    For Each col As DataColumn In table.Columns
      Console.Write(row(col).ToString() & " ")
    Next
    Console.WriteLine()
  Next
End Sub

Remarks

Note

The load operation will fail with an InvalidOperationException if any of the source data columns in the incoming reader are computed columns.

The errorHandler parameter is a FillErrorEventHandler delegate that refers to a procedure that is called when an error occurs while loading data. The FillErrorEventArgs parameter passed to the procedure provides properties that allow you to retrieve information about the error that occurred, the current row of data, and the DataTable being filled. Using this delegate mechanism, rather than a simpler try/catch block, allows you to determine the error, handle the situation, and continue processing if you like. The FillErrorEventArgs parameter supplies a Continue property: set this property to true to indicate that you have handled the error and wish to continue processing; set the property to false to indicate that you wish to halt processing. Be aware that setting the property to false causes the code that triggered the problem to throw an exception.

The name resolution scheme for this method is the same as that followed by the Fill method of the DbDataAdapter class.

Applies to

Partajați prin

DataSet.Load Method

Definition

Overloads

Remarks

Load(IDataReader, LoadOption, DataTable[])

Parameters

Examples

Remarks

See also

Applies to

Load(IDataReader, LoadOption, String[])

Parameters

Examples

Remarks

See also

Applies to

Load(IDataReader, LoadOption, FillErrorEventHandler, DataTable[])

Parameters

Examples

Remarks

See also

Applies to

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