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數據列錯誤資訊

若要避免在DataTable中編輯值時必須響應列錯誤，您可以將錯誤資訊新增至資料列以供稍後使用。 DataRow對象會針對此目的，在每個數據列上提供RowError屬性。 將資料添加至 RowError 的屬性，會將 DataRow 的 HasErrors 屬性設為 true。 若 是 DataRowDataTable 的一部分，且 DataRow.HasErrors 為 真，則 DataTable.HasErrors 屬性也為 真。 這同樣適用於DataTable所屬的DataSet。 在測試錯誤時，你可以檢查 HasErrors 屬性，判斷是否有錯誤資訊被加入到任何列上。 如果HasErrors是真，你可以使用DataTable的GetErrors方法來回傳並只檢查那些有錯誤的列，如下範例所示。

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.";
}

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