我们可以在单个类中编写两个命令，但是我在下面使用了错误“错误77没有方法过载”Endexecutereader'取0个参数'感谢你 [英] Can We Write Two Commands In Single Class I Used Below Code But I Am Getting Following Error"Error 77 No Overload For Method 'Endexecutereader' Takes 0 Arguments " Thank U

问题描述

str = "select Total_Fee from newstd_termfee where termnum='" + comboBox3.Text.Trim() + "'and admin_no='" + txtadmin.Text + "'";
                    str1 = "select  (dueamount/2)  as 'second term' from newstd_termfee";
                    com = new SqlCommand(str, cn);
                    com1 = new SqlCommand(str1,cn);
                    SqlDataReader reader = com.ExecuteReader();
                    SqlDataReader r1 = com1.EndExecuteReader();
                    if (r1.Read())
                    {
                        txttermfee.Text = r1["second term"].ToString();
                    }
                    if (reader.Read())
                    {
                        txttotal.Text = reader["Total_Fee"].ToString();

                    }

                    cn.Close();
                    reader.Close();
                    r1.Close();

推荐答案

这里有几个问题：

1）EndExecuteReader没有不需要参数的版本： MSDN [ ^ ]

2）要使用EndExecuteReader，必须先调用BeginExecuteReader：MSDN [ ^ ]

3）我根本不认为你的意思是EndExecuteReader - 可能，你想要ExecuteReader。

4）你不能当读卡器已在其上打开时，在同一连接上发出第二个命令，因此您需要两个连接才能同时使用两个读卡器。



[edit]

5）正如Richard所说：不要连接字符串来构建SQL命令。它让您对意外或故意的SQL注入攻击持开放态度，这可能会破坏您的整个数据库。请改用参数化查询。 （可以;我相信我没有;不要说...：叹气：

[/ edit]



[edit2]

修复我的c ** k-up：这是Richard，而不是Wes ......：O

[/ edit2]

There are a couple of problems here:
1) EndExecuteReader doesn't have a version that doesn't need a parameter: MSDN[^]
2) To use EndExecuteReader, you must first call BeginExecuteReader first: MSDN[^]
3) I don't think you meant EndExecuteReader at all - probably, you wanted ExecuteReader.
4) You can't issue a second command on the same connection while a reader is already open on it, so you would need two connections to work with two readers simultaneously.

[edit]
5) As Richard said: Do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead. (Can;t believe I didn;t say that... :sigh:
[/edit]

[edit2]
Fix my c**k-up: It was Richard, not Wes...:O
[/edit2]

这篇关于我们可以在单个类中编写两个命令，但是我在下面使用了错误“错误77没有方法过载”Endexecutereader'取0个参数'感谢你的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！