CODEWITHSUNDEEP
c#wpfdatagridtextbox
Heisenberg
Heisenberg

Reputation: 776

WPF Datagrid Column TextBox Allow nullable numerical input C#

I have a Datagrid col binding a nullable int.

<DataGridTextColumn Header = "OVR QTY" Width = "5*" Binding = "{Binding OVERRIDE_QTY, UpdateSourceTrigger = PropertyChanged, StringFormat=N0}"  ElementStyle="{StaticResource STRIKE_THROUGH}">
    <DataGridTextColumn.EditingElementStyle>
        <Style TargetType="{x:Type TextBox}">                                        
            <EventSetter Event="PreviewTextInput" Handler="ODQTY_PreviewTextInput">
            </EventSetter>                                        
        </Style>
    </DataGridTextColumn.EditingElementStyle>
</DataGridTextColumn>

In the code, I try to limit it to numbers and null.

Regex regex = new Regex("^[.][0-9]+$|^[0-9]*[.]{0,1}[0-9]*$|^[0-9]*[ ][0-9]*[/]{0,1}[1-9]*$|^[1-9]*[/]{0,1}[1-9]*$");

private void ODQTY_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
    TextBox tb = sender as TextBox;
        var result = tb.Text.Insert(tb.SelectionStart, e.Text);
        e.Handled = string.IsNullOrEmpty(result) 
            || !regex.IsMatch(result);
}

When I type 1 in the cell, and then type backspace to remove the 1, the datagrid cell won't accept the blank, which I think it is null (correct if I am wrong). Not sure why and how to make it accept null in the cell.

Upvotes: 2

Views: 807

Answers (1)

OptimusPrime
OptimusPrime

Reputation: 301

In your xaml

<DataGridTextColumn Header = "OVR QTY" Width = "5*" Binding = "{Binding OVERRIDE_QTY, UpdateSourceTrigger = PropertyChanged, .......

Add this:

TargetNullValue=''

Look like this

<DataGridTextColumn Header = "OVR QTY" Width = "5*" Binding = "{Binding OVERRIDE_QTY, UpdateSourceTrigger = PropertyChanged, TargetNullValue='', StringFormat=N0}"  ElementStyle="{StaticResource STRIKE_THROUGH}">

I think it'll work.

Upvotes: 2

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