Combobox文本属性twoway绑定不起作用

Question

I have a ComboBox as below

<ComboBox VerticalAlignment="Center"  
          Width="83.84"
          Canvas.Left="626.24"
          Canvas.Top="249.088" DataContext="{Binding Items[0]}"
          Text="{Binding TextVariable, Mode=TwoWay, NotifyOnValidationError=True, TargetNullValue='', ValidatesOnDataErrors=True, ValidatesOnExceptions=True}" 
          Height="68.293" 
          Style="{StaticResource ComboBoxDialogControlQ69_74}" />

The problem is: when I set the value for TextVariable in my view model it gets displayed on UI. But when I change it on UI it is not updated in the property.

I think I am missing something very obvious, any help is appreciated.

Answer 1

It works really good when i tried doing like below for Text binding on ComboBox,

Text="{Binding TextVariable, Mode=TwoWay, UpdateSourceTrigger=LostFocus, NotifyOnValidationError=True, TargetNullValue='', ValidatesOnDataErrors=True, ValidatesOnExceptions=True}" 

I have added one more property to make it editable.

IsEditable="True"

if you need the change on PropertyChange change UpdateSourceTrigger to PropertyChanged

UpdateSourceTrigger=PropertyChanged

VM

 public string TextVariable {
        get 
        { return _TextVariable; }
        set 
        {
            _TextVariable = value; 
            NotifyPropertyChanged(); 
        } 
    }