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How to format and parse a number to/from a TextBox in C#, .NET

Hi experts
I'd done some searches within Experts-Exchange but couldn't find the answer I need. I wonder if someone could help.

I have a TextBox. This TextBox is bound to a BindingSource, which in turn is bound to a data object. I am using two-way bindings.

The member stored in the data object is an integer, eg '412678000'. But it needs to be displayed in decimal up to 3 decimal points. eg. 412.678. (Basically, unit conversion)
Vice versa when user enters the number. He/she enters '412.678' but it shall be stored in the data object as '412678000'.

My data binding code:
tbTxFrequency.DataBindings.Add("Text", bindingSource, "TxFreq", true, DataSourceUpdateMode.OnPropertyChanged, "unknown");

I think I need to add two event handlers (one for Parse, one for Format) to the Data Binding,
eg.
tbTxFrequency.DataBindings["Text"].Format += ConvertHzToMHz;
tbTxFrequency.DataBindings["Text"].Parse += ConvertMHzToHz;

But I don't know how to write these event handlers. Could someone please help? Or should it be done by another way?

Thanks in advance.

BuggyCoder

you can use the format event of your Binding object, here is an example:-

http://msdn.microsoft.com/en-us/library/system.windows.forms.binding.format.aspx

ASKER CERTIFIED SOLUTION

Nasir Razzaq

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dominicwong

ASKER

Thanks CodeCruiser
I am afraid the code doesn't work. Please point to me what I'd done incorrectly.

(1) If I do as the code that was given. There is a compile error.
private void ConvertHzToMHz(object sender, ConvertEventArgs e)
{
e.value = e.value / 1000000 <-- Compile error: Can not apply '/' to operands of type 'object' and 'int'
}

(2) If I cast it as follows, there is a run-time exception of 'InvalidCastException':
e.Value = ((int)(e.Value)) / 1000000.0;
or
e.Value = ((decimal)(e.Value)) / 1000000.0;

Nasir Razzaq

Use a messagebox to see what type e.value is at runtime.

dominicwong

ASKER

Thanks CodeCruiser.

dominicwong

ASKER

Thank you