Generics

haezeban

Hi ,

Quite new to generics, I have a lot of methods with al the same code only the used classobject is different.But I do not know how to make this generic (it gives me errors) :
private void btn_Click(object sender, EventArgs e)
{
ArrayList ar = new ArrayList();
ar.Add("");
this.txtUitleg.Lines = (string[])ar.ToArray(typeof(string));
typeDataSource = typeof(classname1);
typeItems = classname1.Items.GetType();
codeTabel = "classname1";
dataGridView2.DataSource = classname1.Items;
lblTitel.Text = codeTabel;
}

This is the code I have for about 10 different button_clicks events. Only the classname1 is different. So I think this is a good piece of code to use generics.

What I tried :

private void btn_Click(object sender, EventArgs e)
{
GenericsButton_Click();
}

private void GenericsButton_Click()
{
ArrayList ar = new ArrayList();
ar.Add("");
this.txtUitleg.Lines = (string[])ar.ToArray(typeof(string));
typeDataSource = typeof(T);
typeItems = T.Items.GetType();
codeTabel = T.ToString();
dataGridView2.DataSource = T.Items;
lblTitel.Text = codeTabel;
}

But this is not correct. Is it possible to point me out ?
Thanks

4 Replies

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Sam Hobbs16y ago
Yes, I suppose that T.GetType().Name is not correct. I did spend time looking at your code and wrote the T.GetType().Name part rather hastily. The important thing is that what you did have would probably not do what you needed it to do.

As for identifying what button has been clicked (is that what you are asking?), in C++ it is common to derive a class from a control class, and the derived class can have additional data and methods. As far as I know, that is entirely possible using C# too; that is, derive a class from Button. Another possibility is to create a UserControl with a button in it. Another possibility is to use the Tag member of Button (it is a member of the Control class that controls derive from) to have instance-specific data.
haezeban16y ago
Hi,
After a lot of reading. I don't think this method is a good thing to use generic's.
My UI has a lot of button's. All buttons has the same functionality (see example - they fill up a datagrid). The only difference is the used object collection (classname1 in example - I have theis code 50-times but once with classname1, then classname2 etc..... ).

I am looking now to do the following : on each button I will attach the same button_click event (so just 1 time the code), but in that event-code I need to know which collection I need to use.

Is there a way I can give with the event some information ex classname1, calssname2 ...?? Or do I need to test which button is pressed?

tkx
haezeban16y ago
Hi,

Thanks for the answer.
I changed my code, but It gives me the error that T is type parameter, which is not valid in given context.
This on the lines T.Items.GetType() and T.GetType().Name
T will have always the same structure. It is not a standard type as string, Int, double .... It is a self-made class. But always with the same structure.

Tkx,
Sam Hobbs16y ago
What do you mean by "not correct"? Whenever saying things such as that, it is usually necessary to be more specific.

One thing that I see is that for codeTabel you probably need:
codeTabel = T.GetType().Name;