How to show the watermark text in GridNumericColumn of UWP DataGrid?
You can show the PlaceHolderText for GridNumericColumn by loading the SfNumericTextBox as GridNumeriColumn.CellTemplate in UWP DataGrid (SfDataGrid).
Refer to the code snippets to show the PlaceHolderText for GridNumericColumn.
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>