How to Show the Watermark Text in GridNumericColumn of UWP DataGrid?

This sample show cases how to show the watermark text in the UWP DataGrid (SfDataGrid).

You can show the PlaceHolderText for GridNumericColumn by loading the UWP NumericTextBox (SfNumericTextBox) as GridNumeriColumn.CellTemplate in DataGrid.

XAML

<syncfusion:SfDataGrid x:Name="dataGrid"
                    AllowEditing="True"
                    AllowFiltering="True"
                    AllowGrouping="True"
                    AllowDeleting="True"
                    AllowSorting="True" 
                    ColumnSizer="Star"
                    AutoGenerateColumns="False"
                    ItemsSource="{Binding Emp}"
                    ShowGroupDropArea="True">
 
    <syncfusion:SfDataGrid.Columns>
            <syncfusion:GridNumericColumn.CellTemplate>
                <DataTemplate>
                    <input:SfNumericTextBox Value="{Binding Salary,Mode=TwoWay}" PlaceholderText="Type Here" AllowNull="True"/>
                </DataTemplate>
            </syncfusion:GridNumericColumn.CellTemplate>
        </syncfusion:GridNumericColumn>
        <syncfusion:GridTextColumn MappingName="SickLeaveHours"/>
    </syncfusion:SfDataGrid.Columns>
 
</syncfusion:SfDataGrid>

Take a moment to peruse the UWP DataGrid - Getting Started documentation, where you can find about DataGrid with code examples.