Question

C#中connectionString上下文中不存在名称是什么意思

private void button1_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(connectionString);

connectionString="Data Source=localhost;Initial Catalog=数据库名称;User ID=用户名;Password=密码"

try

{

string sql = "select * from YNJDGLXT.dbo where TYNJDGLXT.local用户名=@userName and YNJDGLXT.密码=@UserPassword";

SqlCommand cmd = new SqlCommand(sql, con);

cmd.Parameters.AddWithValue("@userName",txtUserName.Text);

cmd.Parameters.AddWithValue("@Password",txtUserPassword.Text);

con.Open();

//cmd.Connection = con;

SqlDataAdapter da = new SqlDataAdapter(cmd);

DataTable dt = new DataTable();

da.Fill(dt);

if (dt.Rows.Count > 0)

{

MessageBox.Show("成功！");

}

else

{

MessageBox.Show("失败！");

}

}

catch (Exception ex)

{

MessageBox.Show(ex.Message);

}

finally

{

con.Close();

}

}

}

}

Answer 1

SqlConnection con = new SqlConnection(connectionString);

connectionString="Data Source=localhost;Initial Catalog=数据库名称;User ID=用户名;Password=密码"
这两句话的顺序调换下。。

追问

可是换了位置也不行

Answer 2

按钮里面前两句交换一下顺序

Answer 3

变量没声明吧