Looping through submitted form variables is useful when you are receiving the PostBack from an external page or when you are receiving the results from a dynamically created form. Let’s say you have a form with the following fields:

  Name: 
  Age: 
  Location:

You can loop through variables submitted via the method=”POST” method with the following code:

foreach(string key in Request.Form) {
   Response.Write(key + " = " + Request.Form[key] + "");
}

Similarly, you can loop through values submitted using the method=”GET” method by changing Request.Form to Request.QueryString:

foreach(string key in Request.QueryString) {
    Response.Write(key + " = " + Request.QueryString[key] + "");
}

Looping Through Variables of the Same Name

Let’s say you have form variables of the same name you’d like to loop through. For example:

 Checkbox 1
 Checkbox 2
 Checkbox 3
 Checkbox 4

To loop through variables of the same name, you can use the following:

for(int i=0; i < Request.Form.GetValues("ckBox").Length; i++) {
    Response.Write(Request.Form.GetValues("ckBox")[i] + "");
}

Looping Through Form Variables

Let’s say you have dynamically created fields and you’d like to loop through them on the form (click here to download):

<%@ Page Language="C#" %>






  Name: 
  Age: 
  Political Party: 
    
    
    
  
  






Submitted Output:

Once submitted, this code will display the form variables below the submit button (boxed in red):