c# - IF Boolean statement order of input validation -

i have validate inputs user makes, , send error message

this got far

// probes methods check validity. private void btncalculate_click(object sender, eventargs e) {     if (!(validwidth(float.parse(txtwidth.text))))     {         return;     }     if (!(validlength(float.parse(txtlength.text))))     {         return;     }     if (!(validdepth(float.parse(txtavgdepth.text))))     {         return;     } } 

my problem when enter values length, width, , depth. in order..what mean if don't enter width , leave blank , put in length , depth gives me unhandled expection.

here methods

/** created boolean method test if written width valid or not valid **/ private bool validwidth(float width1) {    float width = float.parse(txtwidth.text);     {         if (width >= 2 & width <= 20)         {             return true;         }         else         {             string title = "data invalid";             string msg = "width measurement invalid \n place enter value between 2 , 20";             dialogresult response;              response = messagebox.show(msg, title, messageboxbuttons.ok, messageboxicon.exclamation);             return false;         }     } }  /** created boolean method test if written legnth valid or not valid **/ private bool validlength(float length1) {     float length = float.parse(txtlength.text);     {         if (length >= 5 & length <= 50)         {             return true;         }         else         {             string title = "data invalid";             string msg = "legnth measurement invalid \n place enter value between 5 , 50";             dialogresult response;              response = messagebox.show(msg, title, messageboxbuttons.ok, messageboxicon.exclamation);             return false;         }     } }  /** created boolean method test if written legnth valid or not valid **/ private bool validdepth(float depth1) {     float depth = float.parse(txtavgdepth.text);     if (depth >= 2 & depth <= 4)     {         return true;     }     else     {         string title = "data invalid";         string msg = "average depth measurement invalid \n place enter value between 2 , 4";         dialogresult response;          response = messagebox.show(msg, title, messageboxbuttons.ok, messageboxicon.exclamation);         return false;     } } 

the parse method throw exception if feed empty string. should catch exception, or use tryparse.