Hi,
I am using Xceed Datagrids for WPF 2.0 in my application and I have also provided support for in-line editing of data grids. Please find below the details for the problem that I am facing currently.
Consider there are 3 columns in a grid - ID, FromRegion and ToRegion. All 3 are editable and editor is a textbox.
- Click on ‘FromRegion’ cell.
- Modify the value so that there is no validation error, say 20.
- Now click on any cell of the same row, in this case “ToRegion”. Points to take care of in this step:
- After editing the cell in step 2, do not press ‘Enter’ key or do not click on any other row in the grid.
- This is because as soon as we do the above, the modified value of step 2 will get committed to the underlying data source. We do not want this.
- After clicking in the different cell of the same row, i.e. “ToRegion”, modify its value in such a manner that it will cause a validation error. For e.g. enter -10.
The following code is called on pressing of EndEdit button.
protected void btnEndEdit_Click(object sender, RoutedEventArgs args) {
try{
wfhGrid.EndEdit();
}
catch (DataGridException e1) {
if (wfhGrid.HasValidationError) {
MessageBox.Show("Exception after Validation called. CancelEdit() to be called and application is about to crash. Exception Reason - '" + e1.Message + "'");
wfhGrid.CancelEdit();
}
return ;
}
catch (Exception e)
{
MessageBox.Show("Exception. Validation already called. Exception Reason - '" + e.Message + "'");
return;
}
}
Case 1:
- After modifying “ToRegion” to -10, don’t click anywhere outside the cell. Directly click on “Call EndEdit” button.
- On call of “wfhGrid.EndEdit();” function, valid exception is thrown (since there is a validation error). But then on call of “wfhGrid.CancelEdit();” the following exception is being thrown.
Exception Type: “InvalidOperationException”
Exception Message: “An attempt was made to edit an item that is not part of the specified context.”
Case 2:
- After modifying “ToRegion” to -10, click anywhere outside the cell so that the cell gets painted with a red border.
- Now click on “Call EndEdit” button.
- This time the exception is thrown on call of “wfhGrid.EndEdit();” function itself.
Exception Type: “InvalidOperationException”
Exception Message: “An attempt was made to edit an item that is not part of the specified context.”
Can you please let me know why this is happening and how do I resolve this problem.
I am attaching the source code for reference:
using
System;
using
System.Windows;
using
System.Windows.Controls;
using
System.Windows.Data;
using
Xceed.Wpf.DataGrid;
using
Xceed.Wpf.DataGrid.Markup;
using
Xceed.Wpf.DataGrid.Views;
using
Xceed.Wpf.DataGrid.ValidationRules;
using
System.Globalization;
namespace
DataGridTestApp
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class Window1 : System.Windows.Window
{
AircraftCrew.AircraftCrewDataTable _dtAircraftCrew;
public Window1()
{
_dtAircraftCrew =
new AircraftCrew.AircraftCrewDataTable(); // This is a typed dataset
InitializeComponent();
InitializeGrid();
}
private void InitializeGrid()
{
AircraftCrew.AircraftCrewRow row;
row = _dtAircraftCrew.NewAircraftCrewRow();
row.ID =
Guid.NewGuid();
row.FromRegion = 10;
row.ToRegion = 10;
_dtAircraftCrew.AddAircraftCrewRow(row);
_dtAircraftCrew.AcceptChanges();
wfhGrid.ItemsSource =
new BindingListCollectionView(_dtAircraftCrew.DefaultView);
wfhGrid.ReadOnly =
false;
wfhGrid.EditTriggers =
EditTriggers.CellIsCurrent;
wfhGrid.CellEditorDisplayConditions =
CellEditorDisplayConditions.MouseOverCell;
wfhGrid.ValidationMode =
ValidationMode.CellEndingEdit;
Column column = wfhGrid.Columns["FromRegion"];
column.CellValidationRules.Add(
new MinimumValueCellValidationRule(0));
column = wfhGrid.Columns[
"ToRegion"];
column.CellValidationRules.Add(
new MinimumValueCellValidationRule(0));
}
public class MinimumValueCellValidationRule : CellValidationRule
{
private double m_min;
public MinimumValueCellValidationRule(double min)
{
m_min = min;
}
// The minimum value of the cell content
public override ValidationResult Validate(object value, CultureInfo culture, CellValidationContext context)
{
double number = Convert.ToDouble(value, CultureInfo.CurrentCulture);
if (number < m_min)
{
string message = string.Format("Error");
return new ValidationResult(false, message);
}
return ValidationResult.ValidResult;
}
}
protected void btnEndEdit_Click(object sender, RoutedEventArgs args)
{
try
{
wfhGrid.EndEdit();
}
catch (DataGridException e1)
{
if (wfhGrid.HasValidationError)
{
MessageBox.Show("Exception after Validation called. CancelEdit() to be called and application is about to crash. Exception Reason - '" + e1.Message + "'");
wfhGrid.CancelEdit();
}
return ;
}
catch (Exception e)
{
MessageBox.Show("Exception. Validation already called. Exception Reason - '" + e.Message + "'");
return;
}
}
}
}
