I'm still learning C# and this is really annoying me.

I need to modify the contents of a text box on a windows app from a class.

(Using windows app template on VS 2005)

I have created a property on Form1 (SourcePath is a textbox)



I then have this method on a class called dirinfo.



This will not work, I get this

Quote: Originally Posted by Error An object reference is required for the nonstatic field, method, or property 'Ras.Form1.SourceDir.get'

The thing is that I don't know what the instance for Form1, as far as I can tell there does not appear to an instance of Form1, which does not sound right.

I tried creating an instance of Form1, substituted bold line by this

but unsurprisingly while it compiles, it does not show the path on the textbox.

I know i can make it work by putting
on the Form1 class, but I would like to learn how to do it without resorting to this.

Any ideas?

TIA

Ok, I got it now, but the same line of thought applies. You will have to change your code to look like this:

2. public void dirreader(FolderBrowserDialog folderBrowserDialog, ListBox listBox, Form theForm)
4. {
5. folderBrowserDialog.ShowDialog();
7. theForm.SourceDir = folderBrowserDialog.SelectedPath;
9. listBox.Items.Clear();
11. DirectoryInfo dir = new DirectoryInfo(folderBrowserDialog.SelectedPath);
13. DirectoryInfo[] subdirectories = dir.GetDirectories();
15. FileInfo[] directoryFiles = dir.GetFiles();
17. foreach (FileInfo str in directoryFiles)
18. { listBox.Items.Add(str); }
19. }

and you will call it like this:

1. dirreader(new FolderBrowserDialog, myListBox, this);

this way you are telling your class which Form1 (out of unlimted Form1 that can

be created) is calling the dirreader function, so it will know whichSourceDir propertyto

update.

You should reasearch a little about static methods and also about Reference types

and Value types and the differences between them. And how to properly use them.

Replace Form1.SourceDir with this.SourceDir

this way you are pointing to the correct reference of Form1. Form1 is an object not necessarily the current

Form you see in front of you. You can create as many Form1 as you want but you need the correct instance

of the Form1 to be able to work with it. And you get it using the "this" keyword.

Hope this helps you understand why you are having this problem.

Regards,

Fábio

Hi a1pro,

You declaredSourceDir property on Form1 class whichis not static.

On line 5 You want to update it but in a static context using type name.propety name. This is the line that is raising exception during compile time.

Removing type name gave You instance context and since SourceDir property is an instance property there is no more compile-time exception.

You can read about Static Classes and Static Class Members here.

Regards,

Oleh.

Fabio,

I probably did not explain this too well.

trying [code]this.SourceDir[/code] will not work as dirinfo has no definition of SourceDir.

SourceDir is a property in Form1, where Form1 is the form that one gets when using VS 2005 win app template.

[code]
public partial class Form1 : Form
{

public Form1()
{
InitializeComponent();

}

public string SourceDir
{
get { return SourcePath.Text; }
set { SourcePath.Text = value; }
}



[/code]

Oleh,

I don't quite follow what you mean

Thanks for your replies anyway

Ok, I got it now, but the same line of thought applies. You will have to change your code to look like this:

2. public void dirreader(FolderBrowserDialog folderBrowserDialog, ListBox listBox, Form theForm)
4. {
5. folderBrowserDialog.ShowDialog();
7. theForm.SourceDir = folderBrowserDialog.SelectedPath;
9. listBox.Items.Clear();
11. DirectoryInfo dir = new DirectoryInfo(folderBrowserDialog.SelectedPath);
13. DirectoryInfo[] subdirectories = dir.GetDirectories();
15. FileInfo[] directoryFiles = dir.GetFiles();
17. foreach (FileInfo str in directoryFiles)
18. { listBox.Items.Add(str); }
19. }

and you will call it like this:

1. dirreader(new FolderBrowserDialog, myListBox, this);

this way you are telling your class which Form1 (out of unlimted Form1 that can

be created) is calling the dirreader function, so it will know whichSourceDir propertyto

update.

You should reasearch a little about static methods and also about Reference types

and Value types and the differences between them. And how to properly use them.

That works fine.

I don't know why I didn't think about using this as a parameter for dirreader to ensure that the running instance of form1 would be used.

At any rate, thanks for your help