从gridview页脚文本框添加时，不要在数据库中插入重复值 [英] donot insert duplicate values in database when added from gridview footer textboxes

问题描述

我正在使用asp.net c＃sqlserver 2005数据库。



在我的网页上我有一个gridview，在这个gridview我有4个字段（用户名，密码） ，电子邮件，指定）和页脚中的4个文本框输入记录。和添加按钮以添加记录。



如果记录已存在于数据库中，则显示消息用户名已存在。



先谢谢。



这是我在gridview的行命令中的代码。

I am working on asp.net c# sqlserver 2005 database.

on my webpage i have a gridview, in this gridview i have 4 fields (Username,Password, email,designation) and 4 textboxes in footer to enter the records. and a add button to add the record.

if the record already exists in database, display a message Username already exists.

Thanks in advance.

This is my code in row command in gridview.

protected void GVRegistrations_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        if (e.CommandName.Equals("AddNew Registrations"))
        {
 TextBox TxtUsername  = (TextBox)GVRegistrations.FooterRow.FindControl("TxtFooterUsername");

 TextBox TxtPassword = (TextBox)GVRegistrations.FooterRow.FindControl("TxtFooterPassword");

            TextBox TxtEmail = (TextBox)GVRegistrations.FooterRow.FindControl("TxtFooterEmail");

TextBox TxtDesignation = (TextBox)GVRegistrations.FooterRow.FindControl("TxtFooterDesignation");

            con.Open();
            SqlCommand cmd = new SqlCommand("INSERT into ACRegistrations(Username,Password,Email,Designation) values('" + TxtUsername.Text + "','" + TxtPassword.Text + "','" + TxtEmail.Text + "','" + TxtDesignation.Text + "')", con);
            int result = cmd.ExecuteNonQuery();
            con.Close();
            if (result == 1)
            {
                BindRegistrations();
                ScriptManager.RegisterStartupScript(this, this.GetType(), "RunCode", "javascript:alert('Record Added successfully');", true);
            }
            
        }
    }

这里只是我想添加到代码，如果用户名已经存在。如果我输入相同的用户名onceagain。

here just i want to add to code, that if username already exists. if i enter the same username onceagain.

推荐答案

执行选择查询以检查用户名是否已存在。使用以下查询选择



SELECT *

来自ACRegistrations

WHERE用户名= TxtUsername.text



如果不存在则执行插入查询。

Do a select query for checking whether user name already present. Use below query for select

SELECT *
FROM ACRegistrations
WHERE Username = TxtUsername.text

If its not present then do an insert query.

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