有从DataGridView导入excel的代码，可是excel列宽不会修改。

public static void DataGridViewToExcel(DataGridView dgv)

        {





            #region   验证可操作性



            //申明保存对话框 

            SaveFileDialog dlg = new SaveFileDialog();

            //默然文件后缀 

            dlg.DefaultExt = "xlsx ";

            //文件后缀列表 

            dlg.Filter = "EXCEL文件(*.XLSX)|*.xlsx ";

            //默然路径是系统当前路径 

            dlg.InitialDirectory = Directory.GetCurrentDirectory();

            //打开保存对话框 

            if (dlg.ShowDialog() == DialogResult.Cancel) return;

            //返回文件路径 

            string fileNameString = dlg.FileName;

            //验证strFileName是否为空或值无效 

            if (fileNameString.Trim() == " ")

            { return; }

            //定义表格内数据的行数和列数 

            int rowscount = dgv.Rows.Count;

            int colscount = dgv.Columns.Count;

            //行数必须大于0 

            if (rowscount <= 0)

            {

                MessageBox.Show("没有数据可供保存 ", "提示 ", MessageBoxButtons.OK, MessageBoxIcon.Information);

                return;

            }



            //列数必须大于0 

            if (colscount <= 0)

            {

                MessageBox.Show("没有数据可供保存 ", "提示 ", MessageBoxButtons.OK, MessageBoxIcon.Information);

                return;

            }



            //行数不可以大于65536 

            if (rowscount > 65536)

            {

                MessageBox.Show("数据记录数太多(最多不能超过65536条)，不能保存 ", "提示 ", MessageBoxButtons.OK, MessageBoxIcon.Information);

                return;

            }



            //列数不可以大于255 

            if (colscount > 255)

            {

                MessageBox.Show("数据记录行数太多，不能保存 ", "提示 ", MessageBoxButtons.OK, MessageBoxIcon.Information);

                return;

            }



            //验证以fileNameString命名的文件是否存在，如果存在删除它 

            FileInfo file = new FileInfo(fileNameString);

            if (file.Exists)

            {

                try

                {

                    file.Delete();

                }

                catch (Exception error)

                {

                    MessageBox.Show(error.Message, "删除失败 ", MessageBoxButtons.OK, MessageBoxIcon.Warning);

                    return;

                }

            }

            #endregion

            Microsoft.Office.Interop.Excel.Application objExcel = null;

            Microsoft.Office.Interop.Excel.Workbook objWorkbook = null;

            Microsoft.Office.Interop.Excel.Worksheet objsheet = null;



            try

            {

                //申明对象 

                objExcel = new Microsoft.Office.Interop.Excel.Application();

                objWorkbook = objExcel.Workbooks.Add(System.Reflection.Missing.Value);

                //objsheet = (Microsoft.Office.Interop.Excel.Worksheet)objWorkbook.ActiveSheet;

                objsheet = (Microsoft.Office.Interop.Excel.Worksheet)objWorkbook.Worksheets[1];



                //设置EXCEL不可见 

                objExcel.Visible = false;



                //向Excel中写入表格的表头 

                int displayColumnsCount = 1;

                for (int i = 0; i <= dgv.ColumnCount - 1; i++)

                {

                    if (dgv.Columns[i].Visible == true)

                    {

                        objExcel.Cells[1, displayColumnsCount] = dgv.Columns[i].HeaderText.Trim();

                        displayColumnsCount++;

                    }

                }

                //设置进度条 

                //tempProgressBar.Refresh(); 

                //tempProgressBar.Visible   =   true; 

                //tempProgressBar.Minimum=1; 

                //tempProgressBar.Maximum=dgv.RowCount; 

                //tempProgressBar.Step=1; 

                //向Excel中逐行逐列写入表格中的数据 

                for (int row = 0; row <= dgv.RowCount - 1; row++)

                {

                    //tempProgressBar.PerformStep(); 



                    displayColumnsCount = 1;

                    for (int col = 0; col < colscount; col++)

                    {

                        if (dgv.Columns[col].Visible == true)

                        {

                            try

                            {

                                objExcel.Cells[row + 2, displayColumnsCount] = dgv.Rows[row].Cells[col].Value.ToString().Trim();

                                displayColumnsCount++;

                            }

                            catch (Exception)

                            {



                            }



                        }

                    }

                }

                //--------------调整列宽-------------------//

                objsheet..Columns[1].ColumnWidth = 15;//------------------（此处报错）

                

               

                

                //-------------------------------------------//

                //隐藏进度条 

                //tempProgressBar.Visible   =   false; 

                //保存文件 

                objWorkbook.SaveAs(fileNameString, System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value,

                        System.Reflection.Missing.Value, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlShared, System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value,

                        System.Reflection.Missing.Value, System.Reflection.Missing.Value);

            }

            catch (Exception error)

            {

                MessageBox.Show(error.Message, "警告 ", MessageBoxButtons.OK, MessageBoxIcon.Warning);

                return;

            }

            finally

            {

                //关闭Excel应用 

                if (objWorkbook != null) objWorkbook.Close(System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value);

                if (objExcel.Workbooks != null) objExcel.Workbooks.Close();

                if (objExcel != null) objExcel.Quit();



                objsheet = null;

                objWorkbook = null;

                objExcel = null;

            }

            MessageBox.Show(fileNameString + "导出完毕! ", "提示 ", MessageBoxButtons.OK, MessageBoxIcon.Information);