How to use the command Controls.Add() in C#

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Hi everybody,

I am a newbie with c# and have been trying to implement a very basic dynamic programming of a button.
I googled to look for a solution, but I keep obtaining this error:

'System.Windows.Controls.WrapPanel' does not contain a definition for 'Controls' and no extension method 'Controls' accepting a first argument...

I cannot figure out how to have the button showing up on my window without using this Controls.Add() function.
What am I missing?

Thanks for your help!

C#

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace Simple_Button_Feedback
{
    public partial class MainWindow : Window
    {   
        public MainWindow()
        {
            CreateButton();

            InitializeComponent();
        }

        private void CreateButton()
        {

            Button b = new Button();
            b.Content = "I'm a silly Button";
            b.Click += new RoutedEventHandler(this.ButtonClick);
            b.Height = 25;
            b.Width = 100;
      //      b.Location = new Point(50,50);

            LinearGradientBrush lgb = new LinearGradientBrush();
            lgb.GradientStops.Add(new GradientStop(Colors.Yellow, 0));
            lgb.GradientStops.Add(new GradientStop(Colors.Green, 1));
            b.Background = lgb;
 
      //          this.Controls.Add(b);
      //   A <WrapPanel> named "Panel1" is defined in the .xaml file 
            Panel1.Controls.Add(b);
        }

        protected void ButtonClick(object sender, EventArgs e)
        {
            MessageBox.Show("Click me again.  That felt good.");
        }

    }
}

Posted 30-Mar-12 8:34am

Member 8771971

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[no name] 30-Mar-12 14:43pm

Try panel1.Children.Add

Member 8771971 30-Mar-12 15:30pm

The message error does disappear, but when I debug/run the program, I now have following alert: "targetinvocationexception was unhandled"
Is there a specific way I have to define the <WrapPanel name="Panel1"></WrapPanel> to make it work?

[no name] 30-Mar-12 15:36pm

Yes. You are getting that error because your panel does not exist yet. You have to initialize your components first. InitializeComponent(); CreateButton();

Member 8771971 30-Mar-12 15:46pm

Oh great - Thanks a lot!

Does InitializeComponent() mean that the .xaml.cs file is looking for what has been defined in the .xaml file? I am confused, why changing these 2 lines of code is so important.

[no name] 30-Mar-12 15:50pm

The short answer is that that is the method and parses the xaml and instantiates your window and controls. At the time you was trying to create the button, the window and panel did not exist.

2 solutions

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Wes Aday · Answer 1 · 2012-03-31T16:23:00

Not sure why your solution was deleted but for future reference:

C#

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace Simple_Button_Feedback
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {      
            InitializeComponent();
            CreateButton();
        }

        private void CreateButton()
        {

            Button b = new Button();
            b.Content = "I'm a silly Button";
            b.Click += new RoutedEventHandler(this.ButtonClick);
            b.Height = 25;
            b.Width = 100;
      //      b.Location = new Point(50,50);

            LinearGradientBrush lgb = new LinearGradientBrush();
            lgb.GradientStops.Add(new GradientStop(Colors.Yellow, 0));
            lgb.GradientStops.Add(new GradientStop(Colors.Green, 1));
            b.Background = lgb;

      //          this.Controls.Add(b);
      //   A <WrapPanel> named "Panel1" is defined in the .xaml file
            Panel1.Children.Add(b);
        }

        protected void ButtonClick(object sender, EventArgs e)
        {
            MessageBox.Show("Click me again.  That felt good.");
        }

    }
}

Thilina Chandima · Answer 2 · 2012-03-30T08:42:00

Solution 1

you can use this code to add button dynamically.

C#

private void CreateButton()
{
    Button Button1 = new Button();
    Button1.Name = "Button1";// this is useful to identify the object
    Button1.Location = new Point(25, 25);
    this.Controls.Add(Button1);
}

Posted 30-Mar-12 8:42am

Thilina Chandima

Comments

Member 8771971 30-Mar-12 15:32pm

Thanks for your help! But my problem keeps occuring: "Controls" is underlined and signaled as an error by Visual Studio...