syncfusion : GridComboBoxColumn is not displaying data.

[Jiya]

Hello,

[New to  sfDataGrid, so experimenting and learning ]

I have defined <syncfusion:GridComboBoxColumn> and i am trying to bring the list for GridCombobox at runtime after a button click event.  but list is not being populated. i guess i am doing some silly  mistake. 

  <syncfusion:SfDataGrid              x:Name="grid7"   

            HorizontalAlignment="Left" Height="513" Margin="33,288,0,0"  AllowResizingColumns="True" 

            AutoGenerateColumns="False"                                ColumnSizer="Auto"                                VerticalAlignment="Top" Width="1437">

            <syncfusion:SfDataGrid.Columns>

                <syncfusion:GridTextColumn MappingName="ID"/>

                 .... (other columns )

                <syncfusion:GridTextColumn MappingName="ResField" AllowEditing="True"/>

                <syncfusion:GridComboBoxColumn  HeaderText="" AllowEditing="True"

                                        ItemsSource="{x:Bind  ResObservableCollection}" DisplayMemberPath="Key" SelectedValuePath="Value"

                                        MappingName="ResField" />

Where  ResObservableCollection is  local public variable of type ObservableCollection<Res>  and Class Res is as below 

 public class Res

    {

        public string Key { get; set; }

        public string Value { get; set; }

    }

On Page_Loaded the grid7 gets its items source    grid7.ItemsSource = fl.items;     here items do have few rows, but only ResField will be empty and the role of UI is to accept values for this column from user.  The list of values for GridComboBoxColumn is unknown until user selects a file that has values.

The button_click event retrieves the values from file into ResObservableCollection 

 this.ResObservableCollection =  await resFileReader.ParseAsync(userSelectedFile);

My expectations was that since source is ObservableCollection,  The GridComboBoxColumn  will see the change in underlying source and update the list at runtime automatically.  but that is not happening.. 

Any guidance or alternative approach please.

Regards

[Muthukumar Kalyanasundaram]

Hi Jiya, 

 

Thank you for contacting Syncfusion support. 

 

In SfDataGrid, the GridComboBoxColumn will load the collection when defining DataContext before loading the SfDataGrid. When we are defining the DataContext in Page.Loaded event, the binding will not update for GridComboBoxColumn which loads the empty collection. But you can achieve this by using a DependencyObject class like below code example. 

 

Code Snippet: C# 

public class BindingProxy : DependencyObject 

{ 

    public BindingProxy() { } 

 

    //Dependency property Data for holding ComboBox ItemsSource value. 

 

    public object Data 

    { 

        get { return (object)GetValue(DataProperty); } 

        set { SetValue(DataProperty, value); } 

    } 

 

    // Using a DependencyProperty as the backing store for Data.  This enables animation, styling, binding, etc... 

    public static readonly DependencyProperty DataProperty = 

        DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new PropertyMetadata(null)); 

} 

 

Code Snippet: XAML 

<Page.Resources>         

    <local:BindingProxy x:Key="proxy" Data="{Binding}"/> 

</Page.Resources> 

 

<syncfusion:SfDataGrid.Columns> 

    <!--Binding Dependency object in GridComboBoxColumn--> 

    <syncfusion:GridComboBoxColumn HeaderText="City" ItemsSource="{Binding Data.ItemsCollection, Source={StaticResource proxy}}" AllowEditing="True" 

                                    DisplayMemberPath="Key" SelectedValuePath="Value"  

                                    MappingName="City" /> 

</syncfusion:SfDataGrid.Columns> 

 

 

Sample: http://www.syncfusion.com/downloads/support/forum/135463/ze/GridComboBoxDemo1-123781772 

 

Regarding this, we already have a KB documentation. Could you please refer the below link, 

KB Link: https://www.syncfusion.com/kb/8159/how-to-load-the-collection-in-gridcomboboxcolumn-when-defining-datacontext-after-loading-page 

 

Please let us know if you have any question. 

 

Regards, 

Muthukumar K 

 

[Jiya]

Thanks for reply.  I will surely try this and get back. 

It would be helpful if there is any way to dynamically assign itemsSource to GridComboBoxColumn at runtime.  

Regards

[Jiya]

Hi Muthukumar K ,

I tried your suggestion, but i was not successful, might be because i am not using viewModel.  I am attached my sample code  in your sample project.

All code is there in MyExperiments.xaml.

On start of page, you have to select a resw file (already attached in the project folder) and then grid will show up. 

Regards

Attachment: GridComboBoxDemo1_20c9ce68.zip

[Gnanasownthari Thirugnanam]

Hi Jiya, 

Please find the response for your queries. 

Query 1: dynamically assign ItemsSource to GridComboBoxColumn at runtime.

You can assign the ItemsSource to GridComboBoxColumn at runtime like below code example.  public void AssignItemsSource()  {      //You cna assign the itemsSource at runtime.      ComboItemsSource = this.ItemsCollection;  }  We have prepared the sample based on your requirement, you can download it from below mentioned location.  Sample location: http://www.syncfusion.com/downloads/support/directtrac/general/ze/GridComboBoxDemo-338419722

Query 2: Still GridComboBoxColumn as Empty

We had noticed that in your given code, you had assign the ItemsSource to field instead of property at runtime. Now we have modified the given files in that sample, you can download it from below mentioned location.  Sample location: http://www.syncfusion.com/downloads/support/directtrac/general/ze/GridComboBoxDemo1-1347191728

Please let us know if you need further assistance on this. 

Regards, 

Gnanasownthari T.