How do I display the value I get by multiplying the values from the two comboboxes on the textbox

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In the below code OTRate value does not get passed to the textbox1

<pre><pre><pre>

private void

textBox1_TextChanged(object sender, EventArgs e)
    {
        double OTRate = (double)(comboBox3.SelectedItem) * (int)(comboBox6.SelectedItem);



        textBox1.Text = OTRate.ToString();

    }

What I have tried:

textBox1_TextChanged(object sender, EventArgs e)
{
double OTRate = (double)(comboBox3.SelectedItem) * (int)(comboBox6.SelectedItem);

textBox1.Text = OTRate.ToString();

}

Posted 17-Sep-16 20:32pm

Charvi Janathri

Updated 17-Sep-16 23:49pm

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Richard MacCutchan 18-Sep-16 4:04am

You need to use the debugger to find out whate each value is returning inside this method.

Karthik_Mahalingam 18-Sep-16 4:48am

what value do you get in comboBox3.SelectedItem ?

Charvi Janathri 18-Sep-16 5:24am

it is a value of real data type,user input

Karthik_Mahalingam 18-Sep-16 5:31am

are you getting the correct value in that object

Charvi Janathri 18-Sep-16 5:53am

yes I am I am getting values like 2500.00 for that combobox

2 solutions

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OriginalGriff · Accepted Answer · 2016-09-17T22:47:00

Solution 1

Quote:
does not get passed to the textbox1

Well... that's probably just as well, really.
Look at your code - and I'll rip out the irrelevant stuff - and it's pretty obvious you have a problem:

C#

textBox1_TextChanged(object sender, EventArgs e)
    {
    ...
    textBox1.Text = OTRate.ToString();
    }

So...when Textbox1 changes, you set a new value for Textbox1. Which causes a changed event to occur, and that means you handle the event, which...changes Textbox1 again. And this repeats until everyone gets bored, or you kill the application.

I don't think you want to handle the TextChanged event to do this - and if you do, you certainly don't want to change the text within it!

Posted 17-Sep-16 22:47pm

OriginalGriff

Comments

Charvi Janathri 18-Sep-16 5:28am

Then how can I show the result I get in textbox1?

OriginalGriff 18-Sep-16 5:30am

Probably by not handling it's TextChanged event, but working with the ComboBox's events instead?

Charvi Janathri 18-Sep-16 5:52am

okay then shall i use a button click to handle it and when i use the button click the value i get is always 0, I dont know why it does not give the calculated answer

OriginalGriff 18-Sep-16 6:02am

Start change it slightly, and look at what you get with the debugger:
double d = (double)(comboBox3.SelectedItem);
int i = (int)(comboBox6.SelectedItem);
double OTRate = d * i;
Put a breakpoint on the last line of that, and use the debugger to look at the values in d and i.
We can't do that for you - we don't have access to the comboboxes!

Charvi Janathri 18-Sep-16 6:08am

the problem is i dont know how to debug but now i am learning it Thanku so much for your help I ll do what u said :) Thanks!

OriginalGriff 18-Sep-16 6:25am

It's pretty easy!
Start by putting a breakpoint on the line: put your cursor on the line you want to breakpoint and use the menu: "Debug...Toggle breakpoint". The line will change to a Red background, and a red dot will appear on the left. Click the dot, and it will disappear and so will the red background - clicking there is the fasted way to add and remove breakpoints, so click again and it will come back.
Now run your program in the debugger by pressing F5. When execution reaches the breakpoint, it will stop and let you take over.
There are a lot of things you can do now, but the most basic - and most useful - are "single stepping" and looking at variables.
Looking at variables is easy: hover the mouse over a variable name and the debugger will show you what it contains.
"Single stepping" is executing your program one line at a time, and you can do it using the new toolbar which appeared (hover the mouse over buttons until you find "Step into" and "Step over") for the moment you want "Step over", which is also F10.
Have a go - there is a lot there, but just that little is enough for 90% of bug finding!

Patrice T · Accepted Answer · 2016-09-17T23:49:00

You should learn to use the debugger as soon as possible. Rather than guessing what your code is doing, It is time to see your code executing and ensuring that it does what you expect.

The debugger allow you to follow the execution line by line, inspect variables and you will see that there is a point where it stop doing what you expect.
Debugger - Wikipedia, the free encyclopedia[^]
Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]

The debugger is here to show you what your code is doing and your task is to compare with what it should do.
When the code don't do what is expected, you are close to a bug.