Validating binding, depending on which button is clicked

Question

I searched a lot, but I didn't find the right solution.

I have a TextBox, DataGridView, 3 Buttons and a BindingSource.

When I click my Button 'Change' I set the binding and data are loaded from DataGridView to TextBox, which works:

textBox.DataBindings.Add("text", bindingSource, "Name", true, DataSourceUpdateMode.OnPropertyChanged);

When I click now Button 'Cancel' the binding will be cleared:

textBox.DataBindings.Clear();

but the data is still transferred to the DataGridView. I think it's because of OnPropertyChanged. When I change it to OnValidation, I know it will only be saved, when it's validated.

But how can I validate it or refuse validation? I have 2 Buttons, and depending on whether the 'Save' button or the 'Cancel' button is clicked, it should be transferred to DataGridView or not.

And also with the event

textBox.Validating += textBox_Validating;

I didn't get it running, because this function is called before I can click a button.

How can I achieve this?

Answer 1

You can create binding with DataSourceUpdateMode.Never and store it in a form level variable (field). Then you can use WriteValue method to apply the changes (respectively ReadValue to revert the changes).

Something like this:

form:

Binding nameBinding;

Change button click:

nameBinding = textBox.DataBindings.Add("Text", bindingSource, "Name", true, DataSourceUpdateMode.Never);

Cancel button click:

nameBinding.ReadValue();
textBox.DataBindings.Clear();
nameBinding = null;

Save button click:

nameBinding.WriteValue();
textBox.DataBindings.Clear();
nameBinding = null;