Question

C#连接数据库时，报错“用户'sa'登录失败。该用户与可信SQL Server连接无关联”，但sa用户直接SQL登陆可以

代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace Myschool
{

public partial class Login : Form
{
public string UserType = string.Empty; //获取登录的类型
public string LoginName = string.Empty; //获取登录的名字
public Login()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{

if (DBHelp(user.Text, password.Text, type.Text))
{
this.DialogResult = DialogResult.Yes;
if (type.Text == "管理员") { UserType = "管理员"; }
if (type.Text == "教师") { UserType = "教师"; }
if (type.Text == "学生") { UserType = "学生"; }

}
else
{
MessageBox.Show("用户名或密码错误，请重新输入；");
}

}

public bool DBHelp(string LoginName,string LoginPwd,string LoginType)
{
try
{
MyConnection.myconn.Open();
string s = "";
if (LoginType == "管理员")
{
s = string.Format("select count(*) from Admin where LoginId='{0}' and LoginPwd='{1}'", LoginName, LoginPwd);
}
else if (LoginType == "教师")
{
s = string.Format("select count(*) from Teacher where LoginId='{0}' and LoginPwd='{1}'", LoginName, LoginPwd);
}
else if (LoginType == "学生")
{
s = string.Format("select count(*) from Student where LoginId='{0}' and LoginPwd='{1}'", LoginName, LoginPwd);
}
SqlCommand mycom = new SqlCommand(s, MyConnection.myconn);
int i = (int)mycom.ExecuteScalar();
if (i >= 0)
{
return true;
}
else
return false;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return false;
}
finally
{
MyConnection.myconn.Close();
}

}

private void Login_Load(object sender, EventArgs e)
{

}

private void cancel_Click(object sender, EventArgs e)
{
this.Close();
}

private void type_SelectedIndexChanged(object sender, EventArgs e)
{
}
}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;

namespace Myschool
{
class MyConnection
{
public static SqlConnection myconn = new SqlConnection("server=.\\sqlexpress;database=MySchool;uid=sa;pwd=123");
}
}
用 sql server 2005

Answer 1

数据库连接设置的问题或者是用户名sa不存在或没权限。

看图设置下试试

Answer 2

数据库服务没打开吧.

Answer 3

服务器身份验证要选择sql server 和windows 身份验证模式

Answer 4

连接数据库的字符串写错了

Answer 5

SqlCommand mycom = new SqlCommand(s, MyConnection.myconn);
mycom.opne();
需要open啊