菜鸟要用customvalidator写个用户名已存在的验证控件，大家帮我看看哪错了

[derek3]

protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
{
DBHelper.connection.Open();//DBHelper是之前写的一个类
string sql = string.Format("select count(*) from Account where UserName='{0}'", this.TextBox1.Text);
DBHelper.cmd.CommandText = sql; DBHelper.cmd.Connection = DBHelper.connection;
int check = Convert.ToInt32(DBHelper.cmd.ExecuteScalar());
if (check == 1)
{
CustomValidator1.IsValid = false;

}
else
{
CustomValidator1.IsValid=true;
}
DBHelper.connection.Close();
}

[derek3]

...........

[derek3]

帮帮忙啊

[wuyq11]

在ServerValidate事件中查询数据库,如果有IsValid=false
check>0
或AJAX验证
http://topic.csdn.net/u/20100206/19/c283adf2-9638-475a-b76f-86f0e1eacf27.html

[derek3]

protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
{
DBHelper.connection.Open();
string sql = string.Format("select count(*) from Account where UserName='{0}'", TextBox1.Text);
DBHelper.cmd.CommandText = sql; DBHelper.cmd.Connection = DBHelper.connection;
int check = Convert.ToInt32(DBHelper.cmd.ExecuteScalar());
if (check >0)
{
args.IsValid = false;


}
else
{
args.IsValid=true;
}
DBHelper.connection.Close();
}


还是要靠自己啊