Iterating through a viewbag of selectlist items

Robbie Hegarty

7y8.2k.NET

Hi folks

I have the following line in a controller:

ViewBag.Assignments = new SelectList(db.class_table_Assignment, "ID", "Title");

In the view (Razor) file I'm looking to iterate through the ViewBag and pull out entries were the ID = "isok"; then populate a DropDownList.

The following line : add_Li_Node(tmp_entry); is where I'm looking to extract the values in the ViewBag. I assumed the for loop would assign the contents of one row of the ViewBag to the variable tmp_entry during each iteration. The actual output I'm getting in the DropDown is "undefined". The for-loop is iterating correctly for the number of rows in the ViewBag.

So basically, I'm asking if anyone can help me iterate through the contents of a ViewBag of SelectList items and view each entry before deciding to keep it.

Thanks in advance.

6 Replies

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Robbie Hegarty7y ago
Thanks Salman

The server side looks like this:

There's no problem here. And as can be seen from the debug window previously, the ViewBag is being populated ok.

All I'm actually looking to do is select an item from one combobox and use it to filter items in another. I know I could send the selection back to the controller and filter from there, but I want to avoid a round trip to the server for something as seemingly basic as this.
Salman Beg7y ago
Hi. If that is the case, then you need to put a debugger in Viewbag where it is assigning the value. Because the client side code looks good but maybe from server side value not coming. Thanks
Robbie Hegarty7y ago
Thanks again.

I amended the "add_Li_Node" line and also entered debugger mode. Here's the for-loop now.
Here's a copy of the output from the debugger. The variable "Available_Assignments" has the information I want, but "tmp_entry" is showing the value "0". So still no further forward.
Salman Beg7y ago
Hi.
In the for loop put debugger; and when you run the program in the browser, just right click on it and select Inspect Element/Inspect/Ctrl+Shift+I and while running the program you can check what are the values you are getting inside tmp_entry variable and based on that you can change your code if you want anything.
For more about debugging you can follow this article,
https://www.geeksforgeeks.org/debugging-in-javascript/
Thanks.
Robbie Hegarty7y ago
Thanks for the reply. But it does not help me. Here's further information:

My for-loop looks like this:

Inside the loop I'm calling the function "add_Li_Node". Here's a copy of the function:

This function and the one containing the loop are contained inside
Salman Beg7y ago
Hi.
To iterate the ViewBag you can use like this,
@foreach (var item in ViewBag.Assignments)
{
//Here in the item you can retrieve all the values and you can manipulate it.
}
Thanks.