Need a 'CellTemplateSelector' similar property in community's DataGrid control

[xiedongweo]

I'm submitting a...

Feature request (UserVoice request: https://wpdev.uservoice.com/forums/110705-universal-windows-platform/suggestions/38030980-need-a-celltemplateselector-relevant-things-in-c)

Current behavior

There's no sucn a property.

Expected behavior

I want such a 'CellTemplateSelector' property. Then, I can choose different dataTemplate for the CellTemplate by my own DataTemplateSelector.

Minimal reproduction of the problem with instructions

Environment

Nuget Package(s): 

Package Version(s): 

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] Insider Build (xxxxx)

Device form factor:
- [x ] Desktop
- [ ] Mobile
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [ ] 2017 (version: )
- [ ] 2017 Preview (version: )

[PaulaScholz]

I want this too.

[xiedongweo]

@PaulaScholz Since the WindowsCommunityToolkit is open source. I spent some time to do some customizations for the DataGrid. Since I have no permission to push the changes to master, so I post the code here.

Open the 'Microsoft.Toolkit.Uwp.UI.Controls.DataGrid.csproj' project and open the 'DataGridTemplateColumn.cs'. Add a 'cellTemplateSelector' property for it like the following:

private DataTemplateSelector _cellTemplateSelector;

public DataTemplateSelector CellTemplateSelector {
        get { return _cellTemplateSelector; }
        set {
            if (_cellTemplateSelector != value)
            {
                _cellTemplateSelector = value;
            }
        }
    }

Edit the 'GenerateElement' method like the following:

 protected override FrameworkElement GenerateElement(DataGridCell cell, object dataItem)
    {
        if (this.CellTemplate != null)
        {
            return this.CellTemplate.LoadContent() as FrameworkElement;
        }

        if (this.CellEditingTemplate != null)
        {
            return this.CellEditingTemplate.LoadContent() as FrameworkElement;
        }

        if (this.CellTemplateSelector != null)
        {
            return this.CellTemplateSelector.SelectTemplate(dataItem).LoadContent() as FrameworkElement;
        }

        if (Windows.ApplicationModel.DesignMode.DesignModeEnabled)
        {
            return null;
        }
        else
        {
            throw DataGridError.DataGridTemplateColumn.MissingTemplateForType(typeof(DataGridTemplateColumn));
        }
    }

Then, you could compile the whole project and use the custom DataGrid control in your UWP project.

<Page.Resources>
    <DataTemplate x:DataType="local:Person" x:Key="template1">
        <StackPanel Orientation="Horizontal" VerticalAlignment="Center" Background="Red">
            <TextBlock Padding="5,0,5,0"
                        Text="{x:Bind FirstName}"/>
            <TextBlock Text="{x:Bind LastName}"/>
        </StackPanel>
    </DataTemplate>
    <DataTemplate x:DataType="local:Person" x:Key="template2">
        <StackPanel Orientation="Horizontal" VerticalAlignment="Center" Background="Green">
            <TextBlock Padding="5,0,5,0"
                        Text="{x:Bind FirstName}"/>
            <TextBlock Text="{x:Bind LastName}"/>
        </StackPanel>
    </DataTemplate>

    <local:CustomCellTemplateSelector x:Key="CellTemplateSelector" template1="{StaticResource template1}" template2="{StaticResource template2}"></local:CustomCellTemplateSelector>
</Page.Resources>
<Grid>
    <DG:DataGrid x:Name="dataGrid1" 
Height="600" Margin="12"
AutoGenerateColumns="False"
ItemsSource="{x:Bind Persons}">
        <DG:DataGrid.Columns>
            <!-- Name Column -->
            <DG:DataGridTemplateColumn Header="Name" CellTemplateSelector="{StaticResource CellTemplateSelector}">
            </DG:DataGridTemplateColumn>
        </DG:DataGrid.Columns>
    </DG:DataGrid>
</Grid>

[RBrid]

I believe that row recycling is throwing a wrench into that idea (it's a DataGrid feature that improves perf). A recycled row by default will not trigger a call to GenerateElement. So recycled rows would normally appear using incorrect cell templates. There is a trick to turn off a row's recycling. See private void UnloadRow(DataGridRow dataGridRow) in DataGridRows.cs:

            // Don't recycle if the row has a custom Style set
            recycleRow &= dataGridRow.Style == null || dataGridRow.Style == this.RowStyle;

You need to set the DataGridRow.Style property on all rows. This is to prevent them from being recycled, but it has perf implications.

[ghost]

This issue has been marked as "Needs: Attention 👋" due to no activity for 7 days. Please triage and assign the issue so the fix can be established.

[ghost]

This issue has been marked as "Needs: Attention 👋" due to no activity for 7 days. Please triage the issue so the fix can be established.

[harinikmsft]

We are not adding features to this DataGrid at this time. Please use @RBrid 's workaround above. If you would like to see this property in the newly proposed WinUI DataGrid, please add a comment in the WinUI discussion issue.