RadGridView with a ComboBox which is binded to a DataTable

[Suresh Krishna]

Hi, 

I have a radgridview binded to a data-table. I need to make the first column of this grid Combo-box. I have tried the following and it did not worked out well as the combo-column is not showing the data-table data.
My code behind,

Class MainWindow

    Private Colours As String()
    Public Sub New()

        ' This call is required by the designer.
        InitializeComponent()
        Colours = New String(1) {}
        Colours(0) = "Yellow"
        Colours(1) = "Green"

        ' Add any initialization after the InitializeComponent() call.
        RadGridView1.ItemsSource = BindData()

    End Sub
    Public Function BindData()
        Dim dtTemp_Start As New DataTable
        If Not dtTemp_Start.Columns.Count > 0 Then
            Dim column As DataColumn = New DataColumn
            column.DataType = System.Type.GetType("System.Int32")
            With column
                .AutoIncrement = True
                .AutoIncrementSeed = 1
                .ReadOnly = True
                .Unique = True
                .ColumnName = "Auto_ID"
            End With
            dtTemp_Start.Columns.Add(column)
            dtTemp_Start.Columns.Add("tType", GetType(String))
            dtTemp_Start.Columns.Add("Expression", GetType(String))
            Dim sDataRow As DataRow
            sDataRow = dtTemp_Start.NewRow()
            sDataRow(1) = "black"
            sDataRow(2) = "bbk"
            dtTemp_Start.Rows.Add(sDataRow)
            ' dtTemp.Columns.Add("VarCollection", GetType(ObservableCollection(Of SimulationVariableInfo)))
            'dtTemp_Start.Columns.Add("ConditionCollection", GetType(clsCondCollection))
        End If
        Return dtTemp_Start
    End Function

    Private Sub RadGridView1_BeginningEdit(ByVal sender As System.Object, ByVal e As Telerik.Windows.Controls.GridViewBeginningEditRoutedEventArgs) Handles RadGridView1.BeginningEdit
        DirectCast(Me.RadGridView1.Columns("tType"), GridViewComboBoxColumn).ItemsSource = Colours
    End Sub
End Class

My XAML,

<telerik:RadGridView IsFilteringAllowed="False" ShowGroupPanel="False" AutoGenerateColumns="false" HorizontalAlignment="Left" Margin="0,67,0,0" Name="RadGridView1" VerticalAlignment="Top" Height="207" Width="503" >
           <telerik:RadGridView.Columns>
               <telerik:GridViewDataColumn Header="ID"  DataMemberBinding="{Binding Auto_ID}" />
               <telerik:GridViewComboBoxColumn  Header="Type"  DataMemberBinding="{Binding tType}"  >

               </telerik:GridViewComboBoxColumn>

               <telerik:GridViewDataColumn Header="Expression"  DataMemberBinding="{Binding Expression}" />
           </telerik:RadGridView.Columns>
       </telerik:RadGridView>

I have attached the output I'm getting. 

I need to retain the value selected in the combo. replacing the original content.
 
regards,

SK

[Pavel Pavlov]

Hello Suresh ,

Please change the Binding in the combo column as follows:
Binding [tType] 

if adding the square brackets does not help let me know so we can investigate the problem further.

Kind regards,
Pavel Pavlov
the Telerik team

[Suresh Krishna]

hi Pavel Pavlov ,

I have tried that, but no change.. Also, one the user selects the combobox item that should be retained in the cell once you deselect the cell.

Help me out with an example.
regards,

[Suresh Krishna]

Hi ,

I have modified the code as shown below,

XAML,

<telerik:GridViewDataColumn Header="ID"  DataMemberBinding="{Binding Auto_ID}" />
               <telerik:GridViewComboBoxColumn  Header="Type"  DataMemberBinding="{Binding [tType]}"  >

Code Behind,

Imports System.Data
Imports Telerik.Windows.Controls

Class MainWindow

    Private Colours As String()
    Public Sub New()
        Try


        ' This call is required by the designer.
        InitializeComponent()
        Colours = New String(1) {}
        Colours(0) = "Yellow"
        Colours(1) = "Green"

            ' Add any initialization after the InitializeComponent() call.
            RadGridView1.ItemsSource = BindData()

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub
    Public Function BindData()
        Dim dtTemp_Start As New DataTable
        If Not dtTemp_Start.Columns.Count > 0 Then
            Dim column As DataColumn = New DataColumn
            column.DataType = System.Type.GetType("System.Int32")
            With column
                .AutoIncrement = True
                .AutoIncrementSeed = 1
                .ReadOnly = True
                .Unique = True
                .ColumnName = "Auto_ID"
            End With
            dtTemp_Start.Columns.Add(column)
            dtTemp_Start.Columns.Add("tType", GetType(String))
            dtTemp_Start.Columns.Add("Expression", GetType(String))
            Dim sDataRow As DataRow
            sDataRow = dtTemp_Start.NewRow()
            sDataRow(1) = "black"
            sDataRow(2) = "bbk"
            dtTemp_Start.Rows.Add(sDataRow)
            ' dtTemp.Columns.Add("VarCollection", GetType(ObservableCollection(Of SimulationVariableInfo)))
            'dtTemp_Start.Columns.Add("ConditionCollection", GetType(clsCondCollection))
        End If
        Return dtTemp_Start
    End Function

    Private Sub RadGridView1_BeginningEdit(ByVal sender As System.Object, ByVal e As Telerik.Windows.Controls.GridViewBeginningEditRoutedEventArgs) Handles RadGridView1.BeginningEdit
        DirectCast(Me.RadGridView1.Columns("[tType]"), GridViewComboBoxColumn).ItemsSource = Colours
    End Sub
End Class

Output on initial Run
output1.jpg (attached)
Output after double click of cell
output2.jpg (attached) 
output3.jpg (attached)  


As you can see in the initial run(output1.jpg) the column is blank!!!


regards

[Suresh Krishna]

Anybody have any idea why its happening?

[Pavel Pavlov]

Hi Suresh ,

While observing your code again to search what may be causing the problem , I have just realized that you are setting the ItemsSource for the combo  column in the beginning edit method. I believe this is part of the trouble. 
Is there any specific reason to set it in the BeginningEdit event handler ? The column will need the ItemsSource even when not in edit mode . 

I may also offer an alternative way of assistance  - if you send me a small project with your data and a Gridview , I will setup the combo column for you and get the project back to you .

Greetings,
Pavel Pavlov
the Telerik team

[Suresh Krishna]

hi,

There is no specific reason i moved the binding in to edit. When I have done the binding after the table binding, I had the same result .

Anyway furnishing the code .
Please look in to this and let me know.
XAML File

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525" xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation">
    <Grid>
        <telerik:RadGridView IsFilteringAllowed="False" ShowGroupPanel="False" AutoGenerateColumns="false" HorizontalAlignment="Left" Margin="0,67,0,0" Name="RadGridView1" VerticalAlignment="Top" Height="207" Width="503" >
            <telerik:RadGridView.Columns>
                <telerik:GridViewDataColumn Header="ID"  DataMemberBinding="{Binding Auto_ID}" />
                <telerik:GridViewComboBoxColumn  Header="Type"  DataMemberBinding="{Binding [tType]}"  >

                </telerik:GridViewComboBoxColumn>

                <telerik:GridViewDataColumn Header="Expression"  DataMemberBinding="{Binding Expression}" />
            </telerik:RadGridView.Columns>
        </telerik:RadGridView>
    </Grid>
</Window>

Code Behind(Vb .net)

Imports System.Data
Imports Telerik.Windows.Controls

Class MainWindow

    Private Colours As String()
    Public Sub New()
        Try


        ' This call is required by the designer.
        InitializeComponent()
        Colours = New String(1) {}
        Colours(0) = "Yellow"
        Colours(1) = "Green"

            ' Add any initialization after the InitializeComponent() call.
            RadGridView1.ItemsSource = BindData()
            DirectCast(Me.RadGridView1.Columns("[tType]"), GridViewComboBoxColumn).ItemsSource = Colours
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub
    Public Function BindData()
        Dim dtTemp_Start As New DataTable
        If Not dtTemp_Start.Columns.Count > 0 Then
            Dim column As DataColumn = New DataColumn
            column.DataType = System.Type.GetType("System.Int32")
            With column
                .AutoIncrement = True
                .AutoIncrementSeed = 1
                .ReadOnly = True
                .Unique = True
                .ColumnName = "Auto_ID"
            End With
            dtTemp_Start.Columns.Add(column)
            dtTemp_Start.Columns.Add("[tType]", GetType(String))
            dtTemp_Start.Columns.Add("Expression", GetType(String))
            Dim sDataRow As DataRow
            sDataRow = dtTemp_Start.NewRow()
            sDataRow(1) = "black"
            sDataRow(2) = "bbk"
            dtTemp_Start.Rows.Add(sDataRow)
            ' dtTemp.Columns.Add("VarCollection", GetType(ObservableCollection(Of SimulationVariableInfo)))
            'dtTemp_Start.Columns.Add("ConditionCollection", GetType(clsCondCollection))
        End If
        Return dtTemp_Start
    End Function

    'Private Sub RadGridView1_BeginningEdit(ByVal sender As System.Object, ByVal e As Telerik.Windows.Controls.GridViewBeginningEditRoutedEventArgs) Handles RadGridView1.BeginningEdit

    'End Sub
End Class

I moved the ComboBoxColumn binding to Init() after the datatable binding
regards,

Suresh

[Pavel Pavlov]

Hello Suresh ,

I have made the fixes neccesary in your code to make things work .  Please find a runnable project attached.


All the best,
Pavel Pavlov
the Telerik team