DataRow.Delete 方法
定义
重要
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删除 DataRow。
public:
void Delete();
public void Delete ();
member this.Delete : unit -> unit
Public Sub Delete ()
例外
示例
以下示例创建包含两列和十行的简单 DataTable 。 使用 Delete 方法删除多个DataRow项后,通过调用 RejectChanges来取消删除其中一行。
private void DemonstrateDeleteRow()
{
// Create a simple DataTable with two columns and ten rows.
DataTable table = new DataTable("table");
DataColumn idColumn = new DataColumn("id",
Type.GetType("System.Int32"));
idColumn.AutoIncrement=true;
DataColumn itemColumn = new DataColumn("item",
Type.GetType("System.String"));
table.Columns.Add(idColumn);
table.Columns.Add(itemColumn);
// Add ten rows.
DataRow newRow;
for(int i = 0; i <10; i++)
{
newRow = table.NewRow();
newRow["item"] = "Item " + i;
table.Rows.Add(newRow);
}
table.AcceptChanges();
DataRowCollection itemColumns = table.Rows;
itemColumns[0].Delete();
itemColumns[2].Delete();
itemColumns[3].Delete();
itemColumns[5].Delete();
Console.WriteLine(itemColumns[3].RowState.ToString());
// Reject changes on one deletion.
itemColumns[3].RejectChanges();
// Change the value of the column so it stands out.
itemColumns[3]["item"] = "Deleted, Undeleted, Edited";
// Accept changes on others.
table.AcceptChanges();
// Print the remaining row values.
foreach(DataRow row in table.Rows)
{
Console.WriteLine(row[0] + "\table" + row[1]);
}
}
Private Sub DemonstrateDeleteRow()
' Create a simple DataTable with two columns and ten rows.
Dim table As New DataTable("table")
Dim idColumn As New DataColumn("id", Type.GetType("System.Int32"))
idColumn.AutoIncrement = True
Dim itemColumn As New DataColumn("item", Type.GetType("System.String"))
table.Columns.Add(idColumn)
table.Columns.Add(itemColumn)
' Add ten rows.
Dim newRow As DataRow
Dim i As Integer
For i = 0 To 9
newRow = table.NewRow()
newRow("item") = "Item " & i.ToString()
table.Rows.Add(newRow)
Next i
table.AcceptChanges()
Dim itemColumns As DataRowCollection = table.Rows
itemColumns(0).Delete()
itemColumns(2).Delete()
itemColumns(3).Delete()
itemColumns(5).Delete()
Console.WriteLine(itemColumns(3).RowState.ToString())
' Reject changes on one deletion.
itemColumns(3).RejectChanges()
' Change the value of the column so it stands out.
itemColumns(3)("item") = "Deleted, Undeleted, Edited"
' Accept changes on others.
table.AcceptChanges()
' Print the remaining row values.
Dim row As DataRow
For Each row In table.Rows
Console.WriteLine(row(0).ToString() & ControlChars.Tab _
& row(1).ToString())
Next row
End Sub
注解
RowState如果行的 已添加,则在调用 AcceptChanges时,RowState将变为 Detached
,并且该行将从表中删除。
在现有 上使用 方法后Delete,变为 RowStateDeleted
。DataRow 它一直保留 Deleted
,直到调用 AcceptChanges。 此时, DataRow 将从表中删除 。
Delete 在循环访问 DataRowCollection 对象时,不应在 foreach 循环中调用。 Delete 修改集合的状态。
可以通过调用 RejectChanges来取消删除已删除的行。
注意
方法 BeginEdit 暂时挂起 RowChanging 事件,但删除操作不会。