通过

行错误信息

为了避免在编辑值 DataTable时对行错误做出响应，可以将错误信息添加到该行供以后使用。 该 DataRow 对象在每一行上提供一个 RowError 属性以实现此目的。 将数据添加到RowError的DataRow属性中，这会将DataRow的HasErrors属性设置为true。 DataRow如果是 DataTable 的一部分，并且 DataRow.HasErrors 为 true，则 DataTable.HasErrors 属性也为 true。 这也适用于 DataSet 所属对象 DataTable 。 测试错误时，可以检查 HasErrors 属性以确定是否已将错误信息添加到任何行。 如果HasErrors是true，你可以使用DataTable的方法GetErrors来返回并仅检查出现错误的行，如以下示例所示。

Dim workTable As DataTable = New DataTable("Customers")
workTable.Columns.Add("CustID", Type.GetType("System.Int32"))
workTable.Columns.Add("Total", Type.GetType("System.Double"))

AddHandler workTable.RowChanged, New DataRowChangeEventHandler(AddressOf OnRowChanged)

Dim i  As Int32

For i  = 0 To 10
  workTable.Rows.Add(New Object() {i , i *100})
Next

If workTable.HasErrors Then
  Console.WriteLine("Errors in Table " & workTable.TableName)

  Dim myRow As DataRow

  For Each myRow In workTable.GetErrors()
    Console.WriteLine("CustID = " & myRow("CustID").ToString())
    Console.WriteLine(" Error = " & myRow.RowError & vbCrLf)
  Next
End If

Private Shared Sub OnRowChanged( _
    sender As Object, args As DataRowChangeEventArgs)
  ' Check for zero values.
  If CDbl(args.Row("Total")) = 0 Then args.Row.RowError = _
      "Total cannot be 0."
End Sub

DataTable  workTable = new DataTable("Customers");
workTable.Columns.Add("CustID", typeof(Int32));
workTable.Columns.Add("Total", typeof(Double));

workTable.RowChanged += new DataRowChangeEventHandler(OnRowChanged);

for (int i = 0; i < 10; i++)
  workTable.Rows.Add(new Object[] {i, i*100});

if (workTable.HasErrors)
{
  Console.WriteLine("Errors in Table " + workTable.TableName);

  foreach (DataRow myRow in workTable.GetErrors())
  {
    Console.WriteLine("CustID = " + myRow["CustID"]);
    Console.WriteLine(" Error = " + myRow.RowError + "\n");
  }
}

protected static void OnRowChanged(
    Object sender, DataRowChangeEventArgs args)
{
  // Check for zero values.
  if (args.Row["Total"].Equals(0D))
    args.Row.RowError = "Total cannot be 0.";
}

另请参阅

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