Row Error Information

To avoid having to respond to row errors while editing values in a DataTable, you can add the error information to the row for later use. The DataRow object provides a RowError property on each row for this purpose. Adding data to the RowError property of a DataRow sets the HasErrors property of the DataRow to true. If the DataRow is part of a DataTable, and DataRow.HasErrors is true, the DataTable.HasErrors property is also true. This applies as well to the DataSet to which the DataTable belongs. When testing for errors, you can check the HasErrors property to determine if error information has been added to any rows. If HasErrors is true, you can use the GetErrors method of the DataTable to return and examine only the rows with errors, as shown in the following example.

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})  
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)  
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.";  

See also