[Solved] Error when exporting GridView with empty column

[Michael Hilgers]

Hey everyone!

I'm using the silverlight GridView in my app.
Now i've created a export function to export the grid content into excel. This is it:

------------------------------
    string extension = "xls";
    SaveFileDialog dialog = new SaveFileDialog()
    {
        DefaultExt = extension,
        Filter = String.Format("{1} Dateien (*.{0})|*.{0}|Alle Dateien (*.*)|*.*", extension, "Excel"),
        FilterIndex = 1
    };
    if (dialog.ShowDialog() == true)
    {
        using (Stream stream = dialog.OpenFile())
        {
            this.radGridView.Export(stream, new GridViewExportOptions()
            {
                Format = ExportFormat.ExcelML,
                Encoding = Encoding.UTF8,
                ShowColumnHeaders = true,
                ShowColumnFooters = true,
                ShowGroupFooters = false,
            });
        }
    }
---------------------------------------

Everything works fine if there are no columns without content. But as soon as one of my columns has no content (because the database query i've done delivered this result) i get the following error message when exporting:

------------------------------------------------------------------------------------------------
Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.

   bei Telerik.Windows.Data.TypeExtensions.DefaultValue(Type type)
   bei Telerik.Windows.Data.Expressions.ExpressionFactory.DefaltValueExpression(Type type)
   bei Telerik.Windows.Data.Expressions.ExpressionFactory.MakeMemberAccess(Expression instance, String memberName, Type memberType)
   bei Telerik.Windows.Data.Expressions.ExpressionFactory.MakeMemberAccess(Expression instance, String memberName, Type memberType, Boolean liftMemberAccessToNull)
   bei Telerik.Windows.Data.Expressions.PropertyAccessExpressionBuilder.CreateMemberAccessExpressionOverride()
   bei Telerik.Windows.Data.Expressions.MemberAccessExpressionBuilderBase.CreateMemberAccessExpression()
   bei Telerik.Windows.Data.Expressions.MemberAccessExpressionBuilderBase.CreateLambdaExpression()
   bei Telerik.Windows.Data.BindingToExpressionExtensions.CreateMemberAccessLambdaExpression(Binding binding, Type objectType, Type memberType)
   bei Telerik.Windows.Data.BindingToExpressionExtensions.CreateUntypedMemberAccessFunc(Binding binding, Type objectType, Type memberType)
   bei Telerik.Windows.Data.BindingToExpressionExtensions.CreateMemberAccessFunc(Binding binding, Type objectType, Type memberType)
   bei Telerik.Windows.Data.DataFieldDescriptorExtensions.CreateMemberAccessFunc(IDataFieldDescriptor fieldDescriptor)
   bei Telerik.Windows.Controls.GridViewBoundColumnBase.InitializeMemberAccessFunc()
   bei Telerik.Windows.Controls.GridViewBoundColumnBase.get_MemberAccessFunc()
   bei Telerik.Windows.Controls.GridViewBoundColumnBase.GetCellContent(Object item)
   bei Telerik.Windows.Controls.GridViewExportWriter.RenderDataCells(Object item)
   bei Telerik.Windows.Controls.GridViewExportWriter.RenderDataRows(IEnumerable items)
   bei Telerik.Windows.Controls.GridViewExportWriter.Render()
   bei Telerik.Windows.Controls.GridView.GridViewDataControl.Export(Stream stream, GridViewExportOptions options)
   bei MPWS.Suppliers_AllArticlesInBBlocks.buttonExport_Click(Object sender, RoutedEventArgs e)
-------------------------------------------------------------------------------------------------------

As soon as i remove the column that can possibly containt no data, the export works perfect.

So is this a bug and what can i do to export the grid even if there are columsn without content?

Regards,
Michael

[Veselin Vasilev]

Hello Michael Hilgers,

I could not reproduce the problem in our Q3 2010 Beta version, can you? Please find attached a sample project (where the Name column is empty) and let me know if it helps.

Regards,
Veselin Vasilev
the Telerik team

[Michael Hilgers]

Hello Veselin Vasilev,

as you can guess, we're not using 2010 Q3 Beta for our application. We are using 2010 Q2 SP2 because as far as i know beta versions shouldn't be used for productive environments.

Can't you try to reproduce the issue in 2010 Q2 SP?

Regards,
Michael

[Veselin Vasilev]

Hello Michael Hilgers,

I tried the same project with the 2010.2.924.1040 version but it is working as expected. What happens at your side?

Regards,
Veselin Vasilev
the Telerik team