Custom Windows Forms Control not exporting functions, not showing in tools list, showing as Text

Question

Hi,

I have written a very simple control. C# Visual Studio 2008. Its output should be, and is a dll. I have added a reference to the dll within the project that I intend to use it with. The msdn article about how to write a control states that it should appear in the 'Add reference / projects' list, which it doesn't but I simply navigated to it under the 'browse' tab, went to the /bin folder and added the reference that way. I dragged it over to my toolbox, but it shows up as a 'Text:xhair_tool' and when i try and add it to a form, it won't, so what have I done wrong? It was created as a 'Windows forms control' project. It should export the one method which is 'Target' which return an array, as shown below.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;

namespace xhair_tool
{
public partial class xhair : UserControl
{
    public xhair()
    {
        InitializeComponent();
    }

    private void xhair_Load(object sender, EventArgs e)
    {

    }
    protected override void OnPaint(PaintEventArgs e)
    {
        Graphics g = e.Graphics;
        Pen pen = new Pen(Color.Black, 1);
        SolidBrush redBrush = new SolidBrush(Color.Red);
        g.DrawLine(pen, 8, 0, 8, 7);
        g.DrawLine(pen, 8, 9, 8, 16);
        g.DrawLine(pen, 0, 8, 7, 8);
        g.DrawLine(pen, 9, 8, 16, 8);

        //ControlPaint.DrawReversibleLine(start, end, backColor)
    }
    /// <summary>
    /// Returns the point at the center of the crosshair
    /// </summary>
    /// <returns>int[x,y]</returns>
    public int[] Target
    {
        get
        {
            int[] _xy = new int[2];
            _xy[0] = this.Left + 8;
            _xy[1] = this.Top + 8;
            return _xy;
        }
    }

}

}

Thanks, R.

Answer 1

Right-click the toolbox, click Choose Items, and add your control.

Some recommendations for the control:

• Target should be a Point, not an int[].
• UserControl is designed for controls that contain other controls. Since yours does not, you should inherit from Control. See here.

• You should set the following styles:

      SetStyle(ControlStyles.AllPaintingInWmPaint
             | ControlStyles.UserPaint
             | ControlStyles.Opaque
             | ControlStyles.OptimizedDoubleBuffer
             | ControlStyles.ResizeRedraw,
               true);
  

Answer 2

The "drag it over to my toolbox" part cannot work. Right-click the toolbox and select "Choose Items", use the Browse tab.

You are much better off just adding the UserControl to your project instead of putting it in a DLL by itself. When you do, it automatically appears at the top of the toolbox after you compile.