C#导出Excel，某单元格内容长度超过255 的解决方法

只需要將該列首個單元格指定為memo類型就可以了！

C# code

public static void ToExcel(DataTable dtSource, string strPath, string strSheetName)
    {        
        System.Data.OleDb.OleDbConnection OleDb_Conn = new System.Data.OleDb.OleDbConnection();
        OleDb_Conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties='Excel 8.0;HDR=No';" + "Data Source=\"" + strPath + "\"";
        try
        {
            OleDb_Conn.Open();
            System.Data.OleDb.OleDbCommand OleDb_Comm = new System.Data.OleDb.OleDbCommand();
            OleDb_Comm.Connection = OleDb_Conn;
            string strCmd;
            try
            {
                strCmd = "drop table [" + strSheetName + "]";
                OleDb_Comm.CommandText = strCmd;
                OleDb_Comm.ExecuteNonQuery();           
            }
            catch
            {
                
            }
            strCmd = "create Table [" + strSheetName + "](";

            foreach (DataColumn dc in dtSource.Columns)
            {
                strCmd += "[" + dc.ColumnName + "] [color=#FF0000][b]memo[/b][/color],";
            }            

            strCmd = strCmd.Trim().Substring(0, strCmd.Length - 1);
            strCmd += ")";
            OleDb_Comm.CommandText = strCmd;
            OleDb_Comm.ExecuteNonQuery();
            foreach (DataRow dr in dtSource.Rows)
            {
                if (dr.RowState != System.Data.DataRowState.Deleted)
                {
                    strCmd = "insert into [" + strSheetName + "] values(";
                    foreach (DataColumn dc in dtSource.Columns)
                    {
                      
                            strCmd += "'" + dr[dc.ColumnName].ToString().Trim().Replace("'","") + "',";
                    }

                    strCmd = strCmd.Substring(0, strCmd.Length - 1);
                    strCmd += ")";

                    OleDb_Comm.CommandText = strCmd;
                    OleDb_Comm.ExecuteNonQuery();
                }
            }
            OleDb_Conn.Close();
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            OleDb_Conn.Close();
        }
    }

strCmd += "[" + dc.ColumnName + "] memo,";