CODEWITHSUNDEEP
c#.net-4.5
DenaliHardtail
DenaliHardtail

Reputation: 28336

How do I change the value of a query string parameter?

I have a string representation of a URL like this:

http://www.GoodStuff.xxx/services/stu/query?where=1%3D1&text=&objectIds=231699%2C232002%2C231700%2C100646&time=

It's a URL but a string object in my code. How do I change the value of objectIds? Do I need to find the string, objectIds, then locate the & before and after, and replace the contents with the desired value? Or is there a better way?

This is a .NET 4.5 FW console app...

Upvotes: 2

Views: 124

Answers (2)

DotNetRussell
DotNetRussell

Reputation: 9863

If you're trying to replace values that are already in there it gets a little more tricky. Try this.

    //Base URL. Doesn't need to be hardcoded. As long as it contains "objectIds=" then it will work
    static string url = @"http://www.GoodStuff.xxx/services/stu/query?where=1%3D1&text=&objectIds=231699%2C232002%2C231700%2C100646&time=";


    static void Main(string[] args)
    {
        //Get the start index
        // +10 because IndexOf gets us to the o but we want the index of the equal sign
        int startIndex = url.IndexOf("objectIds=") + 10;

        //Figure out how many characters we are skipping over.
        //This is nice because then it doesn't matter if the value of objectids is 0 or 99999999
        int endIndex = url.Substring(startIndex).IndexOf('&');

        //Cache the second half of the URL
        String secondHalfOfURL = url.Substring(startIndex + endIndex); 

        //Our new IDs to stick in
        int newObjectIDs = 12345;

        //The new URL. 
        //First, we get the string up to the equal sign of the objectIds value
        //Next we put our IDS in.
        //Finally we add on the second half of the URL
        String NewURL = url.Substring(0, startIndex) + newObjectIDs + secondHalfOfURL;

        Console.WriteLine(NewURL);


        Console.Read();
    }

It ain't pretty but it does the work.

Upvotes: 1

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 727047

If the rest of the URL is fixed, you could locate the id manually, and use string.Format and string.Join to insert the IDs into it:

var urlString = string.Format(
    "http://www.GoodStuff.xxx/services/stu/query?where=1%3D1&text=&objectIds={0}&time="
,   string.Join("%", ids)
);

This will insert a %-separated list of ids from your code into the URL template.

Upvotes: 1

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