急呀,如何禁止一个控件重绘!!!!

C# richTextbox的 字体格式颜色等等 【关于字体格式】



设置的是第一个字符的颜色，这时richtextBox的rtf中记录下位置0的颜色，重置text时，在rtf中的位置从位置0开始,因此颜色还是Color.Red,第三次也应该同样如此

richTextBox1.Text = "123";

richTextBox1.Select(0, 1);

richTextBox1.SelectionColor = Color.Red;

richTextBox1.Clear();//清除文本，包括样式

//或richTextBox1.Text="";

richTextBox1.Text = "abc";

richTextBox1.Text = "efg";

这样重置后的文本颜色就会是黑色.



【关键字着色】



public partial class RichTextBox : Form

    ...{

        public RichTextBox()

        ...{

             InitializeComponent();

         }



        private void tSql_TextChanged(object sender, EventArgs e) //文本框改变事件

        ...{

            int index = this.tSql.SelectionStart;    //记录修改的位置

            this.tSql.SelectAll();

            this.tSql.SelectionColor = Color.Black;

string[] keystr =...{ "select ", "from ", "where ", " and ", " or ", " order ", " by ", " desc ", " when ", " case ",

   " then ", " end ", " on ", " in ", " is ", " else ", " left ", " join ", " not ", " null " };

            for (int i = 0; i < keystr.Length; i )

                this.getbunch(keystr[i], this.tSql.Text);



            this.tSql.Select(index, 0);     //返回修改的位置

            this.tSql.SelectionColor = Color.Black;



         }

        public int getbunch(string p, string s) //给关键字上色

        ...{

            int cnt = 0; int M = p.Length; int N = s.Length;

            char[] ss = s.ToCharArray(), pp = p.ToCharArray();

            if (M > N) return 0;

            for (int i = 0; i < N - M 1; i )

{

                int j;

                for (j = 0; j < M; j )

                ...{

                    if (ss[i j] != pp[j]) break;

                 }

                if (j == p.Length)

                ...{

                    this.tSql.Select(i, p.Length);

                    this.tSql.SelectionColor = Color.Blue;

                     cnt ;

                 }

}

            return cnt;



         }



     }

 



 



【绘制颜色提议】



最好的做法是继承RichTextBox，重载新类的Paint方法。 



并且在设置SelectionLength的时候，禁止控件的重绘过程，这样才不会出现被语法高亮的文本有一个突然选中的过程。 



以下2个方法将会对你解决这一问题有很大的帮助. 

[DllImport("user32")] 

private static extern int SendMessage(IntPtr hwnd, int wMsg, int wParam, IntPtr lParam); 

private const int WM_SETREDRAW = 0xB; 



//停止控件的重绘 

private void BeginPaint() 

{ 

SendMessage(yourRichTextBox.Handle, WM_SETREDRAW, 0, IntPtr.Zero); 

} 



//允许控件重绘. 

private void EndPaint() 

{ 

SendMessage(yourRichTextBox.Handle, WM_SETREDRAW, 1, IntPtr.Zero); 

yourRichTextBox.Refresh(); 

}