WPF: Create a dialog / prompt

Great answer of Josh, all credit to him, I slightly modified it to this however:

MyDialog Xaml

    <StackPanel Margin="5,5,5,5">
        <TextBlock Name="TitleTextBox" Margin="0,0,0,10" />
        <TextBox Name="InputTextBox" Padding="3,3,3,3" />
        <Grid Margin="0,10,0,0">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <Button Name="BtnOk" Content="OK" Grid.Column="0" Margin="0,0,5,0" Padding="8" Click="BtnOk_Click" />
            <Button Name="BtnCancel" Content="Cancel" Grid.Column="1" Margin="5,0,0,0" Padding="8" Click="BtnCancel_Click" />
        </Grid>
    </StackPanel>

MyDialog Code Behind

    public MyDialog()
    {
        InitializeComponent();
    }

    public MyDialog(string title,string input)
    {
        InitializeComponent();
        TitleText = title;
        InputText = input;
    }

    public string TitleText
    {
        get { return TitleTextBox.Text; }
        set { TitleTextBox.Text = value; }
    }

    public string InputText
    {
        get { return InputTextBox.Text; }
        set { InputTextBox.Text = value; }
    }

    public bool Canceled { get; set; }

    private void BtnCancel_Click(object sender, System.Windows.RoutedEventArgs e)
    {
        Canceled = true;
        Close();
    }

    private void BtnOk_Click(object sender, System.Windows.RoutedEventArgs e)
    {
        Canceled = false;
        Close();
    }

And call it somewhere else

var dialog = new MyDialog("test", "hello");
dialog.Show();
dialog.Closing += (sender,e) =>
{
    var d = sender as MyDialog;
    if(!d.Canceled)
        MessageBox.Show(d.InputText);
}

The "responsible" answer would be for me to suggest building a ViewModel for the dialog and use two-way databinding on the TextBox so that the ViewModel had some "ResponseText" property or what not. This is easy enough to do but probably overkill.

The pragmatic answer would be to just give your text box an x:Name so that it becomes a member and expose the text as a property in your code behind class like so:

<!-- Incredibly simplified XAML -->
<Window x:Class="MyDialog">
   <StackPanel>
       <TextBlock Text="Enter some text" />
       <TextBox x:Name="ResponseTextBox" />
       <Button Content="OK" Click="OKButton_Click" />
   </StackPanel>
</Window>

Then in your code behind...

partial class MyDialog : Window {

    public MyDialog() {
        InitializeComponent();
    }

    public string ResponseText {
        get { return ResponseTextBox.Text; }
        set { ResponseTextBox.Text = value; }
    }

    private void OKButton_Click(object sender, System.Windows.RoutedEventArgs e)
    {
        DialogResult = true;
    }
}

Then to use it...

var dialog = new MyDialog();
if (dialog.ShowDialog() == true) {
    MessageBox.Show("You said: " + dialog.ResponseText);
}

Edit: Can be installed with nuget https://www.nuget.org/packages/PromptDialog/

I just add a static method to call it like a MessageBox:

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    x:Class="utils.PromptDialog"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    WindowStartupLocation="CenterScreen" 
    SizeToContent="WidthAndHeight"
    MinWidth="300"
    MinHeight="100"
    WindowStyle="SingleBorderWindow"
    ResizeMode="CanMinimize">
<StackPanel Margin="5">
    <TextBlock Name="txtQuestion" Margin="5"/>
    <TextBox Name="txtResponse" Margin="5"/>
    <PasswordBox Name="txtPasswordResponse" />
    <StackPanel Orientation="Horizontal" Margin="5" HorizontalAlignment="Right">
        <Button Content="_Ok" IsDefault="True" Margin="5" Name="btnOk" Click="btnOk_Click" />
        <Button Content="_Cancel" IsCancel="True" Margin="5" Name="btnCancel" Click="btnCancel_Click" />
    </StackPanel>
</StackPanel>
</Window>

And the code behind:

public partial class PromptDialog : Window
{
    public enum InputType
    {
        Text,
        Password
    }

    private InputType _inputType = InputType.Text;

    public PromptDialog(string question, string title, string defaultValue = "", InputType inputType = InputType.Text)
    {
        InitializeComponent();
        this.Loaded += new RoutedEventHandler(PromptDialog_Loaded);
        txtQuestion.Text = question;
        Title = title;
        txtResponse.Text = defaultValue;
        _inputType = inputType;
        if (_inputType == InputType.Password)
            txtResponse.Visibility = Visibility.Collapsed;
        else
            txtPasswordResponse.Visibility = Visibility.Collapsed;
    }

    void PromptDialog_Loaded(object sender, RoutedEventArgs e)
    {
        if (_inputType == InputType.Password)
            txtPasswordResponse.Focus();
        else
            txtResponse.Focus();
    }

    public static string Prompt(string question, string title, string defaultValue = "", InputType inputType = InputType.Text)
    {
        PromptDialog inst = new PromptDialog(question, title, defaultValue, inputType);
        inst.ShowDialog();
        if (inst.DialogResult == true)
            return inst.ResponseText;
        return null;
    }

    public string ResponseText
    {
        get
        {
            if (_inputType == InputType.Password)
                return txtPasswordResponse.Password;
            else
                return txtResponse.Text;
        }
    }

    private void btnOk_Click(object sender, RoutedEventArgs e)
    {
        DialogResult = true;
        Close();
    }

    private void btnCancel_Click(object sender, RoutedEventArgs e)
    {
        Close();
    }
}

So you can call it like:

string repeatPassword = PromptDialog.Prompt("Repeat password", "Password confirm", inputType: PromptDialog.InputType.Password);