How to keep a running total on postback?

Question

2.50/5 (2 votes)

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I have a a textbox where the user would enter a score. When a button is click that score would be entered in a listbox and the textbox would be cleared.

The problem is that I want to keep a running total. For example if 3 is entered then total should be 3, next when 7 is entered total should be 10.

What I have tried:

int total;
            ViewState["total"] = 0; 
            int num = Convert.ToInt32(txtScore.Text);
            total = total + num;
            Label1.Text = total.ToString();

Posted 1-Mar-17 2:29am

Member 9331278

Updated 1-Mar-17 2:53am

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Comments

Karthik_Mahalingam 1-Mar-17 8:40am

what is the significance of listbox here ?

Member 9331278 1-Mar-17 8:46am

As a record, to store a category and the score.
And later transfer all the categories and score to a database.

Karthik_Mahalingam 1-Mar-17 8:48am

Is listbox related to this issue?

Member 9331278 1-Mar-17 8:52am

no, the listbox has nothing to do with it

Karthik_Mahalingam 1-Mar-17 8:57am

OkJust sum up the data and display?

2 solutions

Solution 1

Use a hidden field[^]

Posted 1-Mar-17 2:37am

Graeme_Grant

Comments

Member 9331278 1-Mar-17 8:48am

thanks for you response. Can you be more specific?

Graeme_Grant 1-Mar-17 8:54am

The link provided has a lot more information with examples of how to use it - did you look at it?

Think of a hidden field as a variable. You can write to it and you can read it.

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jgakenhe · Accepted Answer · 2017-03-01T02:53:00

Solution 2

You can do it a bunch of different ways, such as hidden fields above. To do it using ViewState I would do the following.

int total;
int num = Convert.ToInt32(txtScore.Text);
if (ViewState["total"] == null)
{
	total = 0;
}
else
{
	total = (int)ViewState["total"] + num;
}
ViewState["total"] = total;
Label1.Text = total.ToString();

Posted 1-Mar-17 2:53am

jgakenhe

Comments

Graeme_Grant 1-Mar-17 8:59am

Yep, it all gets packed into the page.

Member 9331278 1-Mar-17 9:02am

thank for the response. However there is a slight problem.
the first score is not being added. For example if 3 is entered total= 0, next 4 is added total = 4 then 5 is added total = 9

Graeme_Grant 1-Mar-17 9:07am

if you set a breakpoint and step through the code, you can see what is happening. Here is the fix:

if (ViewState["total"] == null)
{
	total = num;
}

Please do yourself a big favor and learn how to use the debugger, it will save you hours of work! Basic Debugging with Visual Studio 2010 - YouTube[^]

Member 9331278 1-Mar-17 9:10am

Thanks it works appreciated very much

jgakenhe 1-Mar-17 9:42am

Thanks Graeme.

Graeme_Grant 1-Mar-17 9:44am

All good ... :)