在C#中查询SQLServer的中数据表中的信息

Question

我想实现这样一个功能：
在我用Windows Forms窗体界面验证用户登录信息时，想从我SQLServer服务器的数据库中的一张数据表查询有没有这个用户的相关信息，如果有，则在消息框中提示有这个人；如果没有，则在消息框中说没有这个人。
注：使用的SQLServer版本为2019，使用的代码编辑器为Visual Studio 2019，在Visual Studio中已连接此服务器。

非常感谢帮助。

Answer 1

Hi @KerryZY

first this is an English spoken/written forum, it would be nice if you could write your question in English.

second - my translator said - you want to implement a Form and want to get some information from this SQL Server...

For example you could use this tutorial for connecting your application to SQL Server and grep those information:
https://www.c-sharpcorner.com/UploadFile/5d065a/tutorial-1sql-server-database-connection-in-window-form/

If this is not your plan, then tell us more details about your question/problem.

Answer 2

Hi @KerryZY , Welcome to Microsoft Q&A.

Please refer to the same question I replied in Stack overflow.

Simple login and verification

Edit：

private void Button1_Click(object sender, EventArgs e)   
{  
    //Personal test database  
    string myconn = "your conn";  
    SqlConnection conn = new SqlConnection(myconn);  
    string sql= $"select * from Test.dbo.demoAccount where userid=@UserId";  
        try  
        {  
        conn.Open();  
        SqlCommand sqlCommand = new SqlCommand(sql, conn);  
        sqlCommand.Parameters.Add("@UserId", SqlDbType.VarChar, 8).Value = AccountTb.Text.Trim();      
        SqlDataReader sqlDataReader = sqlCommand.ExecuteReader()；  
        if (sqlDataReader.HasRows) //Satisfy the user name , enter the next interface  
        {  
            MessageBox.Show("There is this person.");  
        }   
        else  
        {  
           MessageBox.Show("There is no such person");  
        }  
  
        conn.Close();  
    }   
    catch (Exception o)  
    {  
        MessageBox.Show(o.ToString());  
    }  
}  

Best Regards,
Jiale

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