/// <summary>
///导出到txt
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void tsExportToTxt_Click(object sender, EventArgs e)
{
System.Windows.Forms.SaveFileDialog objSave = new System.Windows.Forms.SaveFileDialog();
objSave.Filter = "(*.txt)|*.txt|" + "(*.*)|*.*";
objSave.FileName = "CallHistory.txt";
if (objSave.ShowDialog() ==