'cmd.executereader（）;出错“ [英] Error on 'cmd.executereader(); '

问题描述

我想通过在C＃代码و中选择gridview记录来移动rezomekh.aspx页面，我在这一行上收到错误：

 dr = cmd.ExecuteReader（）; 

和错误文字是：

关键字'from'附近的语法不正确。 
描述：执行当前Web请求期间发生了未处理的异常。请查看堆栈跟踪以获取有关错误及其源自代码的位置的更多信息。 
异常详细信息：System.Data.SqlClient.SqlException：关键字'from'附近的语法不正确。

我尝试了什么：

 受保护  void  GridView1_RowCommand（ object  sender，GridViewCommandEventArgs e）
 {
  string  usnam = e.CommandArgument.ToString（）; 
 尝试 
 {
 如果（e.CommandName == < span class =code-string>  rezome）
 {
  string  query =  从Ordertb中选择，其中Username = @ username; 
 
 SqlCommand cmd =  new  SqlCommand（query，con）; 
 cmd.Parameters.AddWithValue（  @ username，usnam）; 
 
 con.Open（）; 
 SqlDataReader dr; 
 dr = cmd.ExecuteReader（）; 
 dr.Read（）; 
会话[  usernamekh] = dr [ 用户名]。ToString（）; 
  //   ViewState [userId] = usId;  
 cmd.ExecuteNonQuery （）; 
 con.Close（）; 
 Response.Redirect（  rezomekh.aspx）; 
} 
 
} 
 最后 
 {
 con.Close（）; 
} 
} 

解决方案

查看您的查询：

 字符串 query =  从Ordertb中选择其中Username = @ username; 

没有指示要返回哪些列。按您希望的顺序列出它们：

  string  query =  从Ordertb中选择MyColumn1，MyColumn2，其中Username = @ username; 

或全部返回（不推荐）：

  string  query =  从Ordertb中选择*，其中Username = @ username; 

查询

字符串query =从Ordertb中选择，其中Username = @ username; 

似乎是错误的，如果它不是拼写错误，那么它应该是选择<列名>来自

I want to move rezomekh.aspx page by choosing a record of gridview in C# codeو and i get error on this line:

dr = cmd.ExecuteReader();

and error text is:

Incorrect syntax near the keyword 'from'.
 Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
 Exception Details: System.Data.SqlClient.SqlException: Incorrect syntax near the keyword 'from'.

What I have tried:

protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
    string usnam = e.CommandArgument.ToString();
    try
    {
        if (e.CommandName == "rezome")
        {
            string query = "select from Ordertb where Username=@username";

            SqlCommand cmd = new SqlCommand(query, con);
            cmd.Parameters.AddWithValue("@username", usnam);

            con.Open();
            SqlDataReader dr;
            dr = cmd.ExecuteReader();
            dr.Read();
            Session["usernamekh"] = dr["Username"].ToString();
            //ViewState["userId"] = usId;
            cmd.ExecuteNonQuery();
            con.Close();
            Response.Redirect("rezomekh.aspx");
        }

    }
    finally
    {
        con.Close();
    }
}

解决方案

Look at your query:

string query = "select from Ordertb where Username=@username";

There is no indication of which columns to return. List them in the order you want them:

string query = "select MyColumn1, MyColumn2 from Ordertb where Username=@username";

Or return them all (not recommended):

string query = "select * from Ordertb where Username=@username";

the query

string query = "select from Ordertb where Username=@username";

seems wrong, if its not a typo, it should be "Select <column name> from "

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