C#上傳文件之打開文檔

//瀏覽按鈕的事件
        private void btnExcelFilePath_Click(object sender, EventArgs e)
        {
            openFileDialog1.Filter = "Files(*.txt)|*.txt";
            openFileDialog1.RestoreDirectory = true;
            openFileDialog1.FilterIndex = 1;
            openFileDialog1.AddExtension = true;
            openFileDialog1.CheckFileExists = true;
            openFileDialog1.CheckPathExists = true;
            DialogResult dr = openFileDialog1.ShowDialog(this);
            if (dr == DialogResult.OK)
            {
                txtExcelFilePath.Text = openFileDialog1.FileName;
            }
        }