Question

I am using a usercontrol inside a grid. This usercontrol contains a textbox that is bound a property of an object supplied by the viewmodel. My problem is the property can be rather a string or a int.

I set the dependency property to be a string so it’s working fine for displaying but if the user enters a string into a int field, no validation error is thrown by the view model but of course i can’t save to the database.

usercontrol XAML

<UserControl x:Class="GenericFileTransferClient.Views.UserControlTextBox"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid Name="GridLayout">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="3*"/>
            <ColumnDefinition Width="7*"/>
        </Grid.ColumnDefinitions>
        <TextBlock Text="{Binding Path=LabelText}" VerticalAlignment="Center" Style="{StaticResource ResourceKey=TextBlockWrapping}" />
        <DockPanel Grid.Column="1">
            <Border DockPanel.Dock="Right"
                                ToolTip="" Style="{StaticResource BorderReportDetail}">
                <TextBlock Text="?" Style="{StaticResource TextBoxReportDetail}"></TextBlock>
            </Border>
            <TextBox Text="{Binding Path=TextBoxText}"/>
        </DockPanel>
    </Grid>
</UserControl>

usercontrol code behind

public partial class UserControlTextBox : UserControl
{
    public static DependencyProperty LabelTextProperty = DependencyProperty.Register("LabelText", typeof(String), typeof(UserControl));
    public static DependencyProperty TextBoxTextProperty = DependencyProperty.Register("TextBoxText", typeof(String), typeof(UserControl));


    public String LabelText
    {
        get { return (String)GetValue(LabelTextProperty); }
        set { SetValue(LabelTextProperty, value); }
    }

    public String TextBoxText
    {
        get { return (String)GetValue(TextBoxTextProperty); }
        set { SetValue(TextBoxTextProperty, value); }
    }

    public UserControlTextBox()
    {
        InitializeComponent();
        GridLayout.DataContext = this;
    }
    }

example of call of the usercontrol in the main grid

<views:UserControlTextBox LabelText="Report Name:" TextBoxText="{Binding Path=CurrentReport.ReportName}" Grid.Row="1" Grid.ColumnSpan="2"/>

            <TextBlock Text="Header:" Grid.Row="2"/>
            <CheckBox Grid.Column="1" Grid.Row="2" IsChecked="{Binding Path=CurrentReport.Header}" 
                      VerticalContentAlignment="Stretch" VerticalAlignment="Center" Name="HeaderCheckBox"/>

            <Grid Grid.Row="3" Grid.ColumnSpan="2" Visibility="{Binding IsChecked, ElementName=HeaderCheckBox, Converter={StaticResource BoolToVisConverter}}">

                <views:UserControlTextBox LabelText="# Row Header:" TextBoxText="{Binding Path=CurrentReport.HeaderRow}"/>
            </Grid>

As you can see, CurrentReport.ReportName is a string but CurrentReport.HeaderRow is a int.

Is there any way to make the dependency property generic or based on a parameter passed to the usercontrol. Or is there any way of having validation to kick in before the user clicks the save button?

Thank you

Answer 1

I would write a simple IntToStringConverter and then use that in your TextBoxText binding to pass in a string to your usercontrol.