ToggleButton in C# WinForms

You can just use a CheckBox and set its appearance to Button:

CheckBox checkBox = new System.Windows.Forms.CheckBox(); 
checkBox.Appearance = System.Windows.Forms.Appearance.Button; 

Check FlatStyle property. Setting it to "System" makes the checkbox sunken in my environment.

thers is a simple way to create toggle button. I test it in vs2010. It's perfect.

ToolStripButton has a "Checked" property and a "CheckOnClik" property. You can use it to act as a toggle button

tbtnCross.CheckOnClick = true;

OR

    tbtnCross.CheckOnClick = false;
    tbtnCross.Click += new EventHandler(tbtnCross_Click);
    .....

    void tbtnCross_Click(object sender, EventArgs e)
    {
        ToolStripButton target = sender as ToolStripButton;
        target.Checked = !target.Checked;
    }

also, You can create toggle button list like this:

        private void Form1_Load(object sender, EventArgs e)
    {
        arrToolView[0] = tbtnCross;
        arrToolView[1] = tbtnLongtitude;
        arrToolView[2] = tbtnTerrain;
        arrToolView[3] = tbtnResult;
        for (int i = 0; i<arrToolView.Length; i++)
        {
            arrToolView[i].CheckOnClick = false;
            arrToolView[i].Click += new EventHandler(tbtnView_Click);
        }
        InitTree();
    }

    void tbtnView_Click(object sender, EventArgs e)
    {
        ToolStripButton target = sender as ToolStripButton;
        if (target.Checked) return;
        foreach (ToolStripButton btn in arrToolView)
        {
                btn.Checked = false;
                //btn.CheckState = CheckState.Unchecked;
        }
        target.Checked = true;
        target.CheckState = CheckState.Checked;

    }