DevExpress TreeList用法总结

http://blog.itpub.net/29251214/viewspace-774395/

http://blog.csdn.net/czp_huster/article/details/50184691

http://www.cnblogs.com/Lixinhua-GoOn/p/4046042.html

dev treelist控件，显示3角符，或显示+ -符的控制

解决方案1：

在 program.cs中把 下面一句暂时注解，你就会发现所有的 treelist会自动显示 + -号;

如果放出来，就显示3角符

DevExpress.LookAndFeel.UserLookAndFeel.Default.SetSkinStyle("DevExpress Style");

解决方案2：

自己画+-号

private void treeList1_CustomDrawNodeButton(object sender, DevExpress.XtraTreeList.CustomDrawNodeButtonEventArgs e)
{
    Brush backBrush = new System.Drawing.Drawing2D.LinearGradientBrush(e.Bounds, Color.White, Color.Black,
em.Drawing.Drawing2D.LinearGradientMode.ForwardDiagonal);
    e.Graphics.FillRectangle(backBrush, e.Bounds);
    // painting 3D borders
    ControlPaint.DrawBorder3D(e.Graphics, e.Bounds, Border3DStyle.Flat);  

    // determining the character to display
    string displayCharacter = e.Expanded ? "-" : "+";
    // formatting the output character
    StringFormat outCharacterFormat = new StringFormat();
    outCharacterFormat.Alignment = StringAlignment.Center;
    outCharacterFormat.LineAlignment = StringAlignment.Center;  

    // painting the character
    e.Graphics.DrawString(displayCharacter, new Font("Verdana", 8),
      new SolidBrush(Color.White), e.Bounds, outCharacterFormat);  

    // prohibiting default painting
    e.Handled = true;  

}