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+---- Thread: c# listbox problem (/showthread.php?tid=3830)
- Nikolee - 07-12-2014
Hey dudes,
i got a problem with ma Listbox.
Im trying to acess the listbox from a nonstatic class, but i always get the error that something is null (object reference).
The Text cant be null cuz i set the string manually but seems like the Listbox is null i tried many diffrent ways but cant handle it.
Here some snippets;
/*--just for test--*/
MainForm frm = new MainForm();
frm.listBox1.Items.Add("xy");
/* throws error */
/*-- example --*/
frm.listBox1 = new System.Windows.Forms.ListBox();
frm.listBox1.Items.Add("TEST");
/* Dont throws an error but text still empty */
I also tried to call a method from the mainform to fill it still didnt worked.
- Nikolee - 07-14-2014
Solved solution for someone who may need it:
First mistake:
Create a constructor in your Class:
private MainForm nMainForm;
public myClassName(MainForm mainForm)
{
nMainForm = mainForm;
}
/*Call it like this*/
public void urFunc()
{
nMainForm.listBox1.Items.Add("test");
}
But theres another thing u need to set up a constructor in the mainform for your Class:
public urClassName myClass;
//now initialize it in the mainform
public MainForm()
{
myClass = new urClassName(this);
}