使用GetCaretPostScript（），系统说外部对象，且没有任何属性。要求添加一个DllImport属性以指定外部实现

要求在状态栏显示光标所在位置
public partial class Form1 : Form
    {
        //public static extern bool GetCaretPos(ref   System.Drawing.Point lpPoint); 
        public   static   extern   bool   GetCaretPos(ref   System.Drawing.Point   lpPoint);
        private   int   X=0;     
        private   int   Y=0;   
        public Form1()
        {
            InitializeComponent();
               
                   }                       private void toolStripMenuItem2_Click(object sender, EventArgs e)
        {
            
           
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                //MessageBox.Show("Open "+openFileDialog1.FileName );
                // Assign the cursor in the Stream to the Form's Cursor property.
                //this.Cursor = new Cursor(openFileDialog1.OpenFile());
                          
               
                this.richTextBox1.LoadFile(openFileDialog1.FileName,RichTextBoxStreamType.PlainText);
                toolStripStatusLabel1.Text = this.openFileDialog1.FileName;
                Point p = new Point(0);
                GetCaretPos(ref p);
                int pos ;
                pos = this.richTextBox1.GetCharIndexFromPosition(p);
                this.Y = this.richTextBox1.GetLineFromCharIndex(pos);                if (this.Y > 0)
                {
                    int offset = 1;
                    while (this.richTextBox1.Text[pos - offset] != '\n')
                        offset++;
                    this.X = offset;
                    this.Y++;
                }
                else
                {
                    this.X = pos + 1;
                    this.Y = 1;
                }     
                toolStripStatusLabel2.Text = "line: "+this.X.ToString() + "Row: "+this.Y.ToString() ;                this.toolStripProgressBar1.Minimum = 0;
                this.toolStripProgressBar1.Maximum = 10;
                this.toolStripProgressBar1.Step += 1;
                this.toolStripProgressBar1.PerformStep();
            }