如何使用该角色登录 [英] How to login with that role

问题描述

我使用此代码登录回合我不知道我该怎么回事?????我想如果管理员打开form1如果用户打开form2



我尝试过：

i use this code to login in bout i don't know what should i bout in ????? i want if it admin open form1 if user open form2

What I have tried:

SqlDataAdapter sda = new SqlDataAdapter("select count(*)  from tbladmin where username='" + txtusername.Text.Trim() + "' and password='" + txtpassword.Text.Trim() + "'", sqlcon);
            DataTable dtbl = new DataTable();
            sda.Fill(dtbl);



            if (dtbl.Rows[0][0].ToString() == "1")
            {
                SqlDataAdapter sda5 = new SqlDataAdapter("select role from tbladmin where username='" + txtusername.Text.Trim() + "' and password='" + txtpassword.Text.Trim() + "'", sqlcon);
                DataTable ds5 = new DataTable();
                sda5.Fill(ds5);
                String value5 = ds5.Rows[0][0].ToString();
                Debug.WriteLine("value is :   " + value5);
                if (????????? = 'admin')
                { 

推荐答案

您不需要SqlDataAdapter和DataTable来得到一个值，你可以使用更轻量级的 SqlDataReader ，参见这里的示例： [ ^ ]

You don't need SqlDataAdapter and DataTable to get a value, you can use the more lightweight SqlDataReader, see example here: Retrieving Data Using a DataReader | Microsoft Docs[^]

string value5 = reader.GetString(0));

还使用参数化查询，尤其是在像这样的安全敏感查询中！

请参阅： c＃ - 如何使用sql参数进行选择查询？ - 堆栈溢出 [ ^ ]



如果在 tbladmin 中找到值，则表示找到了管理员，其他用户可以在 tbluser 中找到。

Also use parameterized queries, especially in security sensitive queries like this one !
See: c# - How to use sql parameters for a select query? - Stack Overflow[^]

If a value is found in tbladmin, it means that an admin was found, other users can be found in tbluser.

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