在用winform将DataTable导出excel文件时 ，遇到一个难题，请教大家帮看看怎么回事：

窗体Shown的事件中调用AutoExecute是正常的，生成了excel文件。 但是此时再点击窗体上的按钮button 调用 AutoExecute()方法，代码执行到了这地方：_Workbook wbk = wbook.Add(Missing.Value);就没反应了，没报错。


    
public class AutoExecute
    {

public void BeginUpLoad()
        {
            System.Threading.Thread SyncThread = new System.Threading.Thread(new System.Threading.ThreadStart(CreatExcel));
            SyncThread.IsBackground = true;
            SyncThread.Start();
        }


         [DllImport("User32.dll", CharSet = CharSet.Auto)]         public static extern int GetWindowThreadProcessId(IntPtr hwnd, out   int ID);

        /// <summary>         ///         /// </summary>         /// <param name="dt"></param>         public bool CreatExcel(System.Data.DataTable dt)         {             try             {                 if (dt == null || dt.Rows.Count == 0)                 {                     return true;                 }

                Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.Application();                 if (app == null)                 {                     throw new Exception("创建Excel失败");                 }

                app.Visible = false;                 app.UserControl = true;                 app.DisplayAlerts = false;

                int colCount = dt.Columns.Count;                 long rowCount = dt.Rows.Count;                 int num = 1;

               

                Workbooks wbook = app.Workbooks;             

                _Workbook wbk = wbook.Add(Missing.Value);//到了这地方就没反应了，   

              Sheets sheet = wbk.Sheets;                 _Worksheet wsheet = (_Worksheet)sheet.get_Item(1); 

                if (wsheet == null)                 {                     return false;                 }

                for (int i = 0; i < rowCount; i++)                 {                     for (int n = 0; n < colCount; n++)                     {                         wsheet.Cells[1, n + 1] = dt.Columns[n].ColumnName;                     }

                    for (int j = 0; j < colCount; j++)                     {                           wsheet.Cells[i + 2, j + 1] = dt.Rows[i][j].ToString();                                            }                 }                              

    string fileName = "VIP2.xlsx";

                app.ActiveWorkbook.SaveAs(Config.Path + fileName, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, XlSaveAsAccessMode.xlNoChange,                  Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value);

                        LogOperate.WriteSuccess("导出成功" + fileName);

                wbk.Close(false, Missing.Value, Missing.Value);                 app.Quit();                 IntPtr t = new IntPtr(app.Hwnd);          //杀死进程                 int k = 0;                 GetWindowThreadProcessId(t, out k);                 System.Diagnostics.Process p = System.Diagnostics.Process.GetProcessById(k);                 p.Kill();

                System.Runtime.InteropServices.Marshal.ReleaseComObject(wsheet);                 System.Runtime.InteropServices.Marshal.ReleaseComObject(wbook);                 System.Runtime.InteropServices.Marshal.ReleaseComObject(wbk);                 System.Runtime.InteropServices.Marshal.ReleaseComObject(app);                 GC.Collect();

                return true;             }             catch (Exception ex)             {                 throw new Exception("导出失败" + ex.Message);             }         

}}