String Comparison

Question

I have one text box. If anybody enters value like <,>,create,drop etc,The error message will come. I need To avoid that.Also My Visual studio software does not support Valiation controls like regular expression validtor,required field validatr etc,So I cant use regular expression validatior to avoid this sql injection B'coz of this reason I decide to use string comparison to check the textbox value charrecter by charrecter . so I can find out the illegal symbols which entered in the text box. Then I can display the error message... Can anybody help me???

Kirtan Patel · Answer

Sure friend tell me for what purpose you need regex ?

Sibin AA · Answer

This is gud its working.... But when I type a lessthan symbol including some letters without any space the error will message will come

Kirtan Patel · Answer

hi dear the code above i given to you is for that purpose it will not allow any symbols it will only allow only numbers and Alphabets protected void Button1_Click( object sender EventArgs e) { string TextToValidate = TextBox1.Text.Trim(); Regex re = new Regex ( ^[a-zA-Z0-9 ]*$ ); if (re.IsMatch(TextToValidate) == false ) { Page.RegisterClientScriptBlock(    alert(' You can Only use alphabets and Numbers')  ); } }

Sibin AA · Answer

when I type etc... the error will come....... I need the REgex which satisfy only numbers and letters... If any other Symbols comes anywhere in the text box then the regex never stisfy... please help me.....

Sibin AA · Answer

Thank you very much Mr.Kirtan One more problem is there ... that is When we give input like etc like this ... the error will come.. Can U help me with another one suitable reagular expression????? All of the other things are right.. this is the only one problem... Please help meeeeeeeeeeee

Kirtan Patel · Answer

using System.Text.RegularExpressions; at the top of the code Write above it will not show error now. :) Happy Coding:)

Sibin AA · Answer

Wht is regex ?????It displays the error message... Can U explain about the regex????? regex stands for what?? any function name?? any keyword??? please help me.....

Kirtan Patel · Answer

Hi  you can do this without validator control using RegEx take a Look at following code . dont forget to mark Do you like answer please if answer helped you .:) here you dont have to check only if user enters any symbols in TextBox For Preventing SQL Injection you dont have to filter all those create etc words :) protected void Button1_Click( object sender EventArgs e) { string TextToValidate = TextBox1.Text.Trim(); Regex re = new Regex ( ^[a-zA-Z0-9 ]*$ ); if (re.IsMatch(TextToValidate) == false ) { Page.RegisterClientScriptBlock(    alert(' You can Only use alphabets and Numbers')  ); } }

Sibin AA · Answer

In my software The regular expression did not work properly .. there has a little bit of error with regular expression. Also I cant use ajax This VS2003. This is the problem