SQL Select命令中的列名无效 [英] Invalid column name in SQL Select command

问题描述

嗨亲爱的，

我想在ASP.NET中读取一个带select * from ...命令的表，

我写了下面的代码：

hi dears,
I want read a table with "select * from ..." command in ASP.NET,
I wrote the code below:

SqlConnection con = new SqlConnection(@"Data Source=.\sql2008;Initial Catalog=test;Integrated Security=true;");
  string str = "select * from tbluser where flduser='"+TextBox1.Text.Trim() +"' and fldpass=" + TextBox2.Text.Trim();

  SqlCommand command = new SqlCommand(str, con);
  con.Open();
  SqlDataReader reader = command.ExecuteReader();

  string selectedStudentName = Convert.ToString(reader);

我的问题是什么？

它显示如下错误：

无效的coumn名称

what is my problem?
it's showed below error:
invalid coumn name

推荐答案

你不能只是去：

You can't just go:

SqlDataReader reader = command.ExecuteReader();
string selectedStudentName = Convert.ToString(reader);

您需要实际读取db中的值，并使用参数化查询指定您想要的列（如Mike Meinz所说）。

试试这个：

You need to actually read the values from the db, and specify which column you want as weel as (as Mike Meinz says) using a parametrized query.
Try this:

string str = "select * from tbluser where flduser=@USER";
SqlCommand command = new SqlCommand(str, con);
con.Open();
command.Parameters.AddWithValue("@USER", TextBox1.Text.Trim());
SqlDataReader reader = command.ExecuteReader();
string selectedStudentName = "";
if (reader.Read())
   {
   selectedStudentName = (string) reader["NameOoColumnWithUserNameInIt"];
   }

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