Question

I am wondering what am I missing? The binding is not displaying at all in the textbox. These are my codes:

XAML Namespace:

xmlns:c="clr-namespace:mySystem.Workspace"

DataContext and Resources:

<Grid.Resources>
        <c:Parameter x:Key="mySource"/>
    </Grid.Resources>
    <Canvas>
        <Canvas.DataContext>
            <Binding Source="{StaticResource mySource}" />
        </Canvas.DataContext>

Textbox:

<TextBox x:Name="TextBox" Width="159" Height="26" Canvas.Left="36" Canvas.Top="47">
            <TextBox.Text>
                <Binding Path="JobKey" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"/>
            </TextBox.Text>

The class:

namespace mySystem.Workspace
{
  public class Parameter : Object  
  { 

The accessors:

 public BasePar JobKey
 {
   get { return jobKey; }
   set { jobKey = value; }
 }

Answer 1

What does the BasePar implementation look like? Have a look in the Debug Output window to see if you have a line like this:

System.Windows.Data Error: 1 : Cannot create default converter to perform 'two-way' conversions between types 'WpfApplication1.BasePar' and 'System.String'. Consider using Converter property of Binding. BindingExpression:Path=JobKey; DataItem='Parameter' (HashCode=14209755); target element is 'TextBox' (Name='TextBox'); target property is 'Text' (type 'String')

This is telling you that you are trying to bind to the property, but WPF cannot create a 2-way binding, because it cannot convert the text (you type into the TextBox) into a ‘BasePar’ object.

As per David’s suggestion, you could bind to a primitive string type, or alternately (as per the warning message above) you could add a Converter to the binding to convert a string into a BasePar.