Powerful ASP. NET Control---validation controls

After studying the beef brisket, the ASP Learning, all of the knowledge, there is a sense of déjà vu, " Oh, this, in the Beef Brisket press release system. " , but at that time, use is also vaguely, say the use of the validation control, beef brisket in the code error, password, user name errors are used to verify the control, but at that time, just vaguely followed with, now there is a clear cloud to see the feeling of the moon.

1. VS The left-hand toolbox provides us with a powerful set of validation controls

1. From top to bottom, compare controls, user-defined validation controls, scope validation controls, regular expression controls, validation controls are empty, validation rollup controls (a summary of validation information)
   1. To compare the use of controls:

1. to use the user-defined validation control, double-click the " user already exists " control, enter the background code authoring phase:

       protected void CustomValidator1_ServerValidate (Object Source,servervalidateeventargs args)        {           string UserName = args. Value;           SqlConnection con = new SqlConnection ("Server= Liu Ying-pc;database=login;uid=sa; pwd=123456; ");           Con. Open ();           SqlCommand cmd=new SqlCommand ("SELECT count (*) from login whereusername= '" +username+ "'", con);            Intcount=convert.toint32 (cmd. ExecuteScalar ());           if (Count > 0)            {               args. Isvalid=false;            }            else            {               args. IsValid = true;            }           Con. Close ();        }

1. Use of scope validation controls

1. Use of regular expression controls

1. cannot be an empty control using the

1. The validation rollup control collection is the errormessage property.

1. CompareValidator controls,

Well , the function of the validation control is very powerful! than before we output MessageBox Prompt user input information is wrong, simple and beautiful!

Powerful ASP. NET Control---validation controls