Validating DataGrid bound to Datatable

Validating DataGrid bound to Datatable

Posted by: firelex on 7 January 2021, 9:02 pm EST

• 

  firelex

  • Post Options:
  • Link
    Copy
  • Jump To Answer

  Posted 7 January 2021, 9:02 pm EST

  I have a DataTable filled from database.

  
  OleDbDataReader _r;
  DataTabel _dt = new DataTable();
  ...
  _dt.Load(_r);
  
  

  I bind this DataTable to my DataGrid in code behind.

  
  _grd.AutoGenerateColums = true;
  _grd.ItemsSource = _dt.DefaultView;
  
  

  The question is: how can I implement validation for data editing?

  I’ve tried to apply this post https://www.grapecity.com/blogs/validation-using-idataerroinfo-in-wpf-c1datagrid, but in my version of DataGrid there is not property ```
  
  e.Row.ValidationResults

  
  Installed ComponentOne sample in the directory [b]DataGridSamples[/b] uses model-side validation and I couldn't apply it as well.
  
  Any help is appreciated.

• 

  kartik.sagar

  

  • Post Options:
  • Link
    Copy

  Posted 10 January 2021, 5:01 pm EST

  Hi,

  You can use ValidationRule for validating DataGrid bound with DataTable. You can create your validation rules by inheriting the ValidationRule class and then adding them to the Binding’s ValidationRules collection as follows:

  
  column.Binding.ValidationRules.Add(new AgeValidationRule()
  { 
         Min = 18, 
         Max = 45,
  });
  
  

  Please refer to the attached sample for full implementation. (see DataGridValidation.zip)

  Regards,
  
  Kartik

  DataGridValidation.zip

• 

  firelex

  • Post Options:
  • Link
    Copy

  Posted 11 January 2021, 10:07 pm EST

  Thanks kartik.sagar! Your example works great.

  But there is one problem about your example: if I add an new row, enter only the name and leave age empty, no validation takes place: i.e. ```
  
  e.Row.Validate();

• 

  kartik.sagar

  

  • Post Options:
  • Link
    Copy

  Posted 12 January 2021, 5:49 pm EST

  Hi,

  You can validate the new row using DataGrid’s CommittingNewRow event and prevent it from being added to the DataGrid until it contains the valid data.

  Please refer the same from the attached modified sample. (see DataGridValidation_Mod.zip)

  Regards,
  
  Kartik

  DataGridValidation_Mod.zip

• 

  firelex

  • Post Options:
  • Link
    Copy

  Posted 13 January 2021, 11:46 pm EST

  Thanks kartik.sagar! Your example helped me much.

  However I have one more question.
  
  Scenario:

  • CommittingNewRow event is triggered
  • error object is added to the Errors-Collection of NewRow
  • if I start editing the Age-Cell in the new row, the red message “Please enter an age…” is not shown. I can see it if the cursor is over the “!” in the first column, but not near the edited cell.

  How can I fix this?

• 

  kartik.sagar

  

  • Post Options:
  • Link
    Copy

  Posted 14 January 2021, 5:17 pm EST

  Hi,

  ValidationRule shows validation message when the cell value is changed. Therefore, we have to type something in the cell in order to execute the validation logic and show the validation message.

  However, if you want to show the validation message when the cell comes in edit mode then you can use the DataRow’s SetColumnError method to set the validation error message as follows:

  
  rowView.Row.SetColumnError("Age", error);
  
  

  Just in case required you can also use C1ValidationBehavior for highlighting the row containing errors as follows:

  
  <c1:C1DataGrid x:Name="dataGrid"  AutoGeneratingColumn="dataGrid_AutoGeneratingColumn">
        <c1:C1ValidationBehavior.ValidationBehavior>
                <c1:C1ValidationBehavior></c1:C1ValidationBehavior>
        </c1:C1ValidationBehavior.ValidationBehavior>
  </c1:C1DataGrid>
  
  

  Please refer to the same from the attached sample. (see DataGridValidation_Mod2.zip)

  Regards,
  
  Kartik

• 

  kartik.sagar

  

  • Post Options:
  • Link
    Copy

  Posted 14 January 2021, 5:18 pm EST

  DataGridValidation_Mod2.zip

• 

  firelex

  • Post Options:
  • Link
    Copy

  Posted 15 January 2021, 1:38 am EST

  Thank you very much, Kartik! It’s just what I needed!

  Is there any possibility to show the validation message when a combobox cell comes in edit mode?
  
  Using SetColumnError didn’t do it. The cell gets red border, but no message is shown.

  Regards,
  
  firelex

• 

  kartik.sagar

  

  • Post Options:
  • Link
    Copy

  Posted 17 January 2021, 4:29 pm EST

  Hi,

  This seems like a bug so I have escalated it to the devs and will revert back to you when there is any update. [Internal Tracking Id - C1XAML-26806]

  Regards,
  
  Kartik