C# Winforms 基于功能的启用/禁用按钮

Question

I want a button on my winform to be enabled or disabled based on the return value of a particular function. Basically, I'm trying the following code in various places where the function will possible return a different value:

btnNewNotices.Enabled = isSelectedPrinterValid();
this.btnNewNotices.Refresh()

However, this is not working. Why is it when I call the refresh method after the enabled property is changed, that the button does not become enabled? I have to close the form and reopen it before the button properly disables. What is the best way to accomplish what I need here without having to bounce the form?

Answer 1

you can add a Databinding for the Enabled property. if your method is implemented in your Form then you can define a Property

public bool IsSelectedPrinterValid
{
    get{ return this.isSelectedPrinterValid(); }
}

And add a Databinding as following:

btnNewNotices.DataBindings.Add("Enabled", this, "IsSelectedPrinterValid");

You can refresh your value:

btnNewNotices.DataBindings[0].ReadValue();

The common way is to implement a ViewModel containing all Properties and Methods you need and bind your controls to these.

Answer 2

Short answer, but it's pretty straight forward.

Using .Refresh(); causes the button to repaint itself, and resets the Enabled property. There's no reason to use it in your context. Just remove it.

btnNewNotices.Enabled = isSelectedPrinterValid();