Question

I’m trying to get value after window dialog is closed:

public partial class MyDialogWindow: Window
{
    public string selectedItem = "";
    public MyDialogWindow(string selectedItem)
    {
        InitializeComponent();
        this.selectedItem = selectedItem;
    }

    ...
}


// To call dialog
string result = "";
MyDialogWindow dialog = new MyDialogWindow(result);
if (form.ShowDialog().Value)
{
   string res = result;
}

But ‘result’ always is empty. In winforms I can get this result, but in WPF not. So How to return result from window, after it is closed?

Answer 1

Strings don’t work like that in C# – they are immutable.

You could get this to work using the ref keyword as other people have suggested, however this will only work if you set SelectedItem in the constructor, which is a bit unlikely!

The normal way of doing this is to have your dialog expose a property on your dialog:

public partial class MyDialogWindow: Window
{
    public string SelectedItem
    {
        get;
        set;
    {

    // etc...
}

MyDialogWindow dialog = new MyDialogWindow(result);
if (form.ShowDialog().Value)
{
   string res = dialog.SelectedItem;
}

This is the way that other dialogs (such as the open / save file dialogs) work.