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I have a listbox and textbox
I need to add the sum of all values in a listbox and post the total in a textbox including textbox value.

Technology - using windows form
OriginalGriff 4-May-11 5:06am    
And what have you tried so far?

Here is how to do it:

static int Sum(ListBox listBox) {
    int result = 0;
    for (int index = 0; index < listBox.Items.Count; ++index) {
        int value;
        if (!int.TryParse(listBox.Items[index], out value)) continue;
        result += value;
    return result;


int sum = 0;

//what does it mean "including text box value"?
//perhapse, this (optional):
int textBoxValue = 0;
int.TryParse(MyTextBox.Text, out textBoxValue);
sum += textBoxValue;

sum += Sum(MyListBox);

MyTextBox.Text = sum.ToString());

If the numeric type if not int, changes the code accordingly (use double or whatever in Sum).

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Sandeep Mewara 6-May-11 0:01am    
A full good concise code.... what more OP can ask for! 5!
Sergey Alexandrovich Kryukov 6-May-11 0:05am    
Thank you, Sandeep.
Tarun.K.S 6-May-11 2:06am    
Sergey Alexandrovich Kryukov 6-May-11 2:37am    
Thank you, Tarun.
Do it like this :

double total=0;
foreach (object item in listBox1.Items)
    total += (double)item;
txtTotal.Text = total.ToString();

or if you have the values as string, then use double.Parse(item) instead of (double)item.
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Kim Togo 4-May-11 5:24am    
Good answer, 5
Tarun.K.S 4-May-11 5:50am    
Thanks! :)
Tarun.K.S 4-May-11 6:00am    
Sergey Alexandrovich Kryukov 5-May-11 16:53pm    
Tarun, you need to be sure that each element is double. My 4, therefore.
Please see my answer for safer code.
Tarun.K.S 6-May-11 2:04am    
Actually I did mention below my code that, if its a string, you can use Double.Parse. Anyway thanks for the 4.
Another way is u can use Generics and do this in a single line


int total = ListBox1.Items.Cast<listitem>().Select<listitem,>(s => Convert.ToInt32(s.Text)).Aggregate((a, b) => a + b);

but as per KIM TOGO, the short and sweet

ListBox1.Items.Cast<listitem>().Sum(item => int.Parse(item.Text));</listitem>
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nit_singh 4-May-11 5:31am    
try will work
Kim Togo 4-May-11 5:49am    
Nice, love Linq.
What about .Sum(item => int.Parse(item.Text)), more simple ?
My 5 for Linq.
nit_singh 4-May-11 6:13am    
Yes yours solution is simple and sweet...Thanks

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