如果是管理员，则无法读取使用身份验证登录。 [英] Login with auth can't read if admin or not.

问题描述

您好;我试图通过一个简单的登录表单检查某人是否是管理员，我的登录工作，但当我尝试检查管理员是否if语句不起作用。我有一个包含3列的用户名，密码和类型的表。我想检查它是否在类型列中写入Admin。这是我的代码：

Hi; I am trying to check if someone is admin or not with a simple login form, my login works but when i try to check if admin or not that if statement doesn't work. I have a table with 3 column with username, password and type. I want to check if in the type column it writes Admin or not. Here is my code:

private void button1_Click ( object sender , EventArgs e )
                {
                    SqlConnection baglanti = new SqlConnection ( @"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\Mehmet\Documents\Visual Studio 2010\Projects\WindowsFormsApplication1\WindowsFormsApplication1\Database1.mdf;Integrated Security=True;User Instance=True;" );
                    SqlDataAdapter adabtor = new SqlDataAdapter ( "select Type from Log_In where Username='" + UserNametextBox1.Text + "' and Password = '" + PasswordtextBox2.Text + "'",baglanti);
                    DataTable tablo = new DataTable();
                    adabtor.Fill(tablo);
                    if ( tablo.Rows.Count == 1 )
                        {
                        logInToolStripMenuItem.Enabled = false;
                        logOutToolStripMenuItem.Enabled = true;
                        LogInpanel1.Visible = false;
                        Aboutpanel2.Visible = true;
                        //MessageBox.Show ( tablo.Rows [ 0 ] [ 0 ].ToString () ); i use this to see what returns from this code, and code returns the correct value like Admin in this case, i also tryed to change Admin to 1, nothing changed
                        if ( tablo.Rows [ 0 ] [ 0 ].ToString () == "Admin" )
                            {
                            addAUserToolStripMenuItem.Visible = true;
                            MessageBox.Show ( "Yes! An admin!" );
                            }
                        }
                    else
                        MessageBox.Show ( "Username or Password is wrong." );
                }

推荐答案

尝试中和字符串数据可能具有的变体 -

Try neutralizing the variations that you string data can have with something like-

if ( tablo.Rows[0][0].ToString().Trim().ToLower() == "admin" )
{

修剪（）将截断空格。

参考： String.Trim方法（） [ ^ ]

ToLower（）会将所有字符转换为小写字母。

参考： String.ToLower方法 [ ^ ]

只是一个建议：

使用列名而不是索引，例如 -

Trim() will truncate the blank spaces.
Reference: String.Trim Method ()[^]
ToLower() will convert all the characters to lower case.
Reference: String.ToLower Method[^]
Just a suggestion:
Use column name instead of index, like-

if ( tablo.Rows[0]["Type"].ToString().Trim().ToLower() == "ADMIN" )
{

希望，它有帮助：）

Hope, it helps :)

我不知道为什么它有效，什么是修剪。我改变了管理员而不是我去了1和0所以它的工作原理如下：

i have no idea why it works and what is trim. Also i changed Admin instead i went for 1 and 0 so it worked like this:

if ( Convert.ToString ( tablo.Rows [ 0 ] [ 0 ] ).Trim ().ToLower () == "1" )
                            {
                            addAUserToolStripMenuItem.Visible = true;
                            MessageBox.Show ( "haydi" );
                            }

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