Define structs in C# - C# Discussion Boards

10-Aug-02 21:32

Thx for your help

so long...
Mario

vb variants in c#

Anonymous10-Aug-02 9:33

Datagrid sorted, how to refresh data?

10-Aug-02 9:33

Can anyone convert the following vb6 code to c#?

Dim SW As SHDocVw.ShellWindows
Dim IE As SHDocVW.InternetExplorer

Set SW = New ShellWindows
For Each IE In SW
If TypeOf IE.Document Is HTMLDocument Then
Debug.Print IE.hWnd
End If
Next IE

The problem lies in the line "For Each IE In SW" since VB supports typeless variables and C# is typed.

Re: vb variants in c#

Jonathan Tan12-Aug-02 1:09

Jonathan Tan

12-Aug-02 1:09

I don't know if every object in SW is of type InternetExplorer or not. I assume it is not.

Use COM Interop or something like that to get all the SHDocVW objects into the .NET system. Then this should work (not sure about the class names):

<br />
ShellWindows SW = new ShellWindows();<br />
InternetExplorer IE;<br />
foreach (object o in SW)<br />
{<br />
IE = o as InternetExplorer;<br />
if (IE.Document is HTMLDocument) Debug.WriteLine (IE.hWnd);<br />
}<br />
<br />

Hope this helps. Smile | :)

Bar10-Aug-02 7:38

Bar

10-Aug-02 7:38

:(I have a datagrid that I populate from a dataset. When I click on a row, I can use the clicked row to access the data in that row using the dataGrid1.CurrentCell.Rownumber with the following code:

object freq = ds.Tables[0].Rows[dataGrid1.CurrentCell.RowNumber][1];

and all works fine. After I click on a column heading to sort the dataset, and then click in a row, the row number returned is the correct new row, but the Table is not resynced, and I get the data that was at that row in the unsorted table. The following code should fix the problem (maybe):

dataGrid1.DataBind();

but this only works in a web form. I also tried rebinding as follows, but no joy:

dataGrid1.SetDataBinding(ds, "Stations");

Can anyone help?

Thanks, Barry k4mg@arrl.net

RegisterHotKey, small problem

Anonymous10-Aug-02 0:15

Re: RegisterHotKey, small problem

10-Aug-02 0:15

Hi all,

I'm new on C# and I get quite many problems.

One of them is how to register hotkeys with C#.

I entered this line in my class declaration :

[DllImport("user32.dll")] private static extern bool RegisterHotKey(long hWnd, int id, int fsModifiers, int vk);

when I run this line whatever the letter is, it doesn't work and return me false.

bool b = RegisterHotKey(GetForegroundWindow(),100,2, 'J'); // 2 = VK_CONTROL

Please help, thanks all.
Nd.

For those who could get it working, don't forget to unregister your hotkey : bool UnregisterHotKey(long hWnd, int id);

leppie10-Aug-02 0:27

Re: RegisterHotKey, small problem

10-Aug-02 0:27

Anonymous wrote:
bool b = RegisterHotKey(GetForegroundWindow(),100,2, 'J'); // 2 = VK_CONTROL

Im not sure, but that 'J' bit needs to be the VK int defined in the headers, you cant assume (int) 'J' will be the correct value.

Hope this helps Smile | :)

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

Anonymous10-Aug-02 7:01

10-Aug-02 7:01

Thanks leppie for your help, I got the value of VK_J (an example) on the web, it's 0x4A. (My C# doesn't know any constant API variable)

But it doesn't work anyway.

If you need as me the numerical equivalent as WM_TIMER or VK_UP, ... go to :

http://www.vbtt.com/tips/how_to_set_or_query_the_status_of_the_keyboard.html

Nd.

Define structs in C#

leppie9-Aug-02 23:24

9-Aug-02 23:24

Hi all

How do i define structs in C# from their definitions in the header files?
I have scratched C++, but not enough. Frown | :(

I understand most of it except for the following few:

1. How do i get the Layout and its options?
2. What is the equivalent of DWORD, WORD, LCID, etc...
3. How do i calculate the size of the struct? sizeof()?
4. What does the follow do and how/when do i know to define it? [MarshalAs(UnmanagedType.ByValTStr, SizeConst=80)]

Sorry for the lame questions Smile | :)

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

Anyone?

leppie11-Aug-02 2:42

11-Aug-02 2:42

MYrc : A .NET IRC client with C# Plugin Capabilities. See
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Re: Define structs in C#

Eric Gunnerson (msft)12-Aug-02 6:42

Eric Gunnerson (msft)

12-Aug-02 6:42

1. I'm not sure what you're asking. By default, structs in C# have sequential layout. You can go to Explicit layout if you need to control offsets exactly, using the StructLayout attribute.

2. DWORD = int, WORD = short. For others, you'll need to trace through the windows headers to find out how they're defined, and translate to the appropriate type. Handles should be typed as IntPtr.

3. In general, you should rarely need it. If you care about the size after it's marshalled into the unmanaged work, use Marshal.Size() (or is is SizeOf()?)

4. It says that the following string or StringBuilder should be marshalled as an embedded TCHAR array 80 characters wide. Use this when you see something like:
TCHAR value[80];

For other questions, it usually much easier to post the API you're trying to call and what your definition is

Re: Define structs in C#

leppie12-Aug-02 12:19

i install net frameworksdk

12-Aug-02 12:19

Thanx Eric, just what i was looking for, I should manage from here Smile | :)

MYrc : A .NET IRC client with C# Plugin Capabilities. See
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imran_rafique9-Aug-02 21:41

9-Aug-02 21:41

but i couldnot get
System.Configuration.dll
System.Diagnostic.dll
how to get it ?
can any body help?

r00d0034@yahoo.com

leppie9-Aug-02 21:58

9-Aug-02 21:58

You will need to reference them in your project, by default only corlib and System get referenced.

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

imran_rafique9-Aug-02 22:53

9-Aug-02 22:53

i refrence them but error found because they are not in their exact location?

r00d0034@yahoo.com

leppie9-Aug-02 23:09

9-Aug-02 23:09

imran_rafique wrote:
i refrence them but error found because they are not in their exact location?

What do u mean the exact location?

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

imran_rafique10-Aug-02 10:34

10-Aug-02 10:34

because how will i add their refrences if i dont have or they are not available from net framework?
what to do?
if there is an error in a program that need it?

r00d0034@yahoo.com

imran_rafique10-Aug-02 11:09

10-Aug-02 11:09

if i want to add the refrence of system.diagnostic.dll
how will i add u if i dont have the file system.diagnostic.dll ?

r00d0034@yahoo.com

leppie10-Aug-02 11:22

10-Aug-02 11:22

SOrry my 1st answer was a bit misleading Smile | :)

both those namespaces can occur in multiple dll's. They are both in mscorlib.dll and System.dll . Look there Smile | :)

MYrc : A .NET IRC client with C# Plugin Capabilities. See
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how to click a button

imran_rafique9-Aug-02 21:02

9-Aug-02 21:02

if i have the hwnd of a form how to get its child hwnd ?
if i have the only hwnd of the botton then how to click it programatically because its easy to click with its object?
and how to listen a botton for action performed on it if i have only the hwnd of it?

r00d0034@yahoo.com

how to click a button

imran_rafique9-Aug-02 10:47

9-Aug-02 10:47

how to programatically click a button on form?

r00d0034@yahoo.com

Nick Parker9-Aug-02 10:52

Nick Parker

9-Aug-02 10:52

Say you have a button called btnGo you simply call btnGo_Click(sender, e);, it is important to pass the two arguments.

HTH

Nick Parker

Rama Krishna Vavilala9-Aug-02 12:07

Rama Krishna Vavilala

9-Aug-02 12:07

Nick Parker wrote:
Say you have a button called btnGo you simply call btnGo_Click(sender, e);, it is important to pass the two arguments.

Nope, that's not correct? What if there are several event liseteners? You have to use PerformClick method.

Nick Parker9-Aug-02 13:51

Nick Parker

9-Aug-02 13:51

Rama Krishna wrote:
Nope, that's not correct? What if there are several event liseteners? You have to use PerformClick method.

There maybe other methods to do this other than the way that I described above however the follow below does work.

private void cmdSearch_Click(object sender, System.EventArgs e)
{
    if(txtSearch.Text == "")
    {
        MessageBox.Show("Please enter a value to search on");
    }
    else
    {

    }
}

private void txtSearch_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
    if(e.KeyChar == 13)
    {
        cmdSearch_Click(sender, e);
    }
}

I see that the PerformClick creates a click event, but if there are several listeners as you say you would still need a method to differentiate the target. I'm assuming this can be accomplished through either overriding the WndProc or through the usage of a delagate. What do you think, or did I misunderstand what you meant about listeners?

Nick Parker

Rama Krishna Vavilala9-Aug-02 15:36

Rama Krishna Vavilala

9-Aug-02 15:36

We normally add Click handler's like this

cmdSearch.Click += new Eventhandler(this.cmdSearch_Click);

Now it might not be that cmdSearch_Click is the only event handlet some other class may have added it's own event handling function to the delegate chain of the Click event. If you say cmdSearch_Click it will work for one, but waht about other event handlers in the chain? Performlick does that.