How to define a name of a computer on C#?

[Dr. Zharkov]

Hello. To define a name of a computer in project VS 2005 after click of
Button1 on Form1, on Visual Basic such code is used:

Declare Auto Function GetComputerName Lib "kernel32.d ll" _

Alias "GetComputerNam e" (ByVal buf As String, _

ByRef size As Integer) As Integer

Private Sub Button1_Click(B yVal sender As System.Object, _

ByVal e As System.EventArg s) Handles Button1.Click

Dim myComputerName As String = Space(30)

Dim Length As Integer = 30

Dim ReturnValue As Integer

ReturnValue = GetComputerName (myComputerName , Length)

MsgBox("Name of my computer: " & myComputerName)

End Sub

In other same project VS 2005, I have copied this code on Visual C# as
follows:

[System.Runtime. InteropServices .DllImport("ker nel32.dll")]

public static extern int GetComputerName (string buf, ref int size);

private void button1_Click(o bject sender, EventArgs e)

{

string myComputerName = "";

int Length = 30;

int ReturnValue;

ReturnValue = GetComputerName (myComputerName , ref Length);

MessageBox.Show ("Name of my computer: " + myComputerName) ;

}

Building this code occurs without errors, however the name of a computer is
not deduced.

Inform, please, where in a code on C# an error?

Beforehand thanks for the answer, Valeriy, Moskva, Russia.

[Carl Daniel [VC++ MVP]]

Dr. Zharkov wrote:

>
Inform, please, where in a code on C# an error?

http://www.pinvoke.net/default.aspx/...puterName.html

-cd

[Michael A. Covington]

I see one obvious difference:

Dim myComputerName As String = Space(30)

versus

string myComputerName = "";

I don't really know how these things work, but I'd try changing that to:

string myComputerName = " ";

and see if it makes a difference.


"Dr. Zharkov" <va************ @mtu-net.ruwrote in message
news:ur******** ******@TK2MSFTN GP05.phx.gbl...

Hello. To define a name of a computer in project VS 2005 after click of
Button1 on Form1, on Visual Basic such code is used:

Declare Auto Function GetComputerName Lib "kernel32.d ll" _

Alias "GetComputerNam e" (ByVal buf As String, _

ByRef size As Integer) As Integer

Private Sub Button1_Click(B yVal sender As System.Object, _

ByVal e As System.EventArg s) Handles Button1.Click

Dim myComputerName As String = Space(30)

Dim Length As Integer = 30

Dim ReturnValue As Integer

ReturnValue = GetComputerName (myComputerName , Length)

MsgBox("Name of my computer: " & myComputerName)

End Sub

In other same project VS 2005, I have copied this code on Visual C# as
follows:

[System.Runtime. InteropServices .DllImport("ker nel32.dll")]

public static extern int GetComputerName (string buf, ref int size);

private void button1_Click(o bject sender, EventArgs e)

{

string myComputerName = "";

int Length = 30;

int ReturnValue;

ReturnValue = GetComputerName (myComputerName , ref Length);

MessageBox.Show ("Name of my computer: " + myComputerName) ;

}

Building this code occurs without errors, however the name of a computer
is
not deduced.

Inform, please, where in a code on C# an error?

Beforehand thanks for the answer, Valeriy, Moskva, Russia.

[Marc Gravell]

Why use the extern, when you can use System.Environm ent.MachineName ?

(mentioned in the article Carl linked to, but worth mentioning
explicitely.)

Marc

[Dr. Zharkov]

Mr. Michael A. Covington. Many thanks for the recommendation, I have checked
up it, but she has not corrected a error.

Mr. Marc Gravell. Many thanks for the recommendation, but I do not know, how
it to use.

Mr. Carl Daniel.

Many thanks for very useful link. By means of this link, the code is carried
out without errors, shows a name of a computer and has such kind:

[System.Runtime. InteropServices .DllImport("Ker nel32")]

static extern unsafe bool GetComputerName (byte* lpBuffer,

long* nSize);

private void button1_Click(o bject sender, EventArgs e)

{

byte[] buffor = new byte[512];

long size = buffor.Length;

unsafe

{

long* pSize = &size;

fixed (byte* pBuffor = buffor)

{

GetComputerName (pBuffor, pSize);

}

}

System.Text.Enc oding textEnc =

new System.Text.ASC IIEncoding();

MessageBox.Show ("Computer name: " +

textEnc.GetStri ng(buffor));

}

Inform, please, and how this code to write down for Managed Visual C#?

Beforehand thanks for the answer, Valeriy, Moskva, Russia.

[JTC ^..^]

private void button1_Click(o bject sender, EventArgs e)

{

string myComputerName;

myComputerName =
System.Windows. Forms.SystemInf ormation.Comput erName;

MessageBox.Show ("Name of my computer: " +
myComputerName) ;

>
}

Regards JTC ^..^

[Marc Gravell]

Like so:

using System;
class Program {
static void Main() {
string machineName = System.Environm ent.MachineName ;
}
}

Only needs a reference to System; there is a "forms" way to do it, but
that needs more references.

Marc

[Dr. Zharkov]

Mr. Marc Gravell. Many thanks for the help. With your help now such code on
C# correctly shows a name of a computer:

[System.Runtime. InteropServices .DllImport("ker nel32.dll")]

public static extern int GetComputerName (string buf, ref int size);

private void button1_Click(o bject sender, EventArgs e)

{

string myComputerName = System.Environm ent.MachineName ;

int Length = 30;

int ReturnValue;

ReturnValue = GetComputerName (myComputerName , ref Length);

MessageBox.Show ("Name of my computer: " + myComputerName) ;

}

Mr. JazzTheCat. Many thanks for the help. With your help now such code on C#
correctly shows a name of a computer:

[System.Runtime. InteropServices .DllImport("ker nel32.dll")]

public static extern int GetComputerName (string buf, ref int size);

private void button1_Click(o bject sender, EventArgs e)

{

string myComputerName =

System.Windows. Forms.SystemInf ormation.Comput erName;

int Length = 30;

int ReturnValue;

ReturnValue = GetComputerName (myComputerName , ref Length);

MessageBox.Show ("Name of my computer: " + myComputerName) ;

}

Once again many thanks. Valeriy, Moskva, Russia.

[Marc Gravell]

Why this obsession with calling the kernel32 function; in both your
examples *you already have the name*, so you don't need the PInvoke
step. At all.

Marc

[Dr. Zharkov]

Mr. Marc Gravell.

Thanks for your remark. Really, in my last letter the code can be written
down much easier:

private void button1_Click(o bject sender, EventArgs e)

{

MessageBox.Show ("Name of my computer: " +

System.Environm ent.MachineName );

}

I want to understand with a technique of application of dynamic-link library
(DLL).

Excuse me, please, but at me the same request to inform, how to change a
code resulted below, that with help DLL and Managed C# this code deduced a
name of a computer (by analogy to the code resulted earlier on Visual
Basic)?

[System.Runtime. InteropServices .DllImport("ker nel32.dll")]

public static extern int GetComputerName (string buf, ref int size);

private void button1_Click(o bject sender, EventArgs e)

{

string myComputerName = "";

int Length = 30;

int ReturnValue;

ReturnValue = GetComputerName (myComputerName , ref Length);

MessageBox.Show ("Name of my computer: " + myComputerName) ;

}

Beforehand thanks for the answer, Valeriy, Moskva, Russia.