|
i want to invoke GetDIBits function ,this is my code:
-----------------------------------------
public struct BITMAPINFOHEADER
{
public uint biSize; // DWORD
public long biWidth; // LONG
public long biHeight; //LONG
public uint biPlanes; // WORD
public uint biBitCount; // WORD
public uint biCompression; // DWORD
public uint biSizeImage; // DWORD
public long biXPelsPerMeter; // LONG
public long biYPelsPerMeter; // LONG
public uint biClrUsed; // DWORD
public uint biClrImportant; // DWORD
}
public struct RGBQUAD
{
public byte rgbBlue;
public byte rgbGreen;
public byte rgbRed;
public byte rgbReserved;
}
public struct BITMAPINFO
{
public BITMAPINFOHEADER bmiHeader;
public RGBQUAD bmiColors; //
}
code above is the structure definition;
[DllImport("gdi32.dll")]
public static extern int GetDIBits(IntPtr hdc, IntPtr hbmp, uint uStartScan,uint cScanLines, out byte[] lpvBits, ref BITMAPINFO lpbmi, uint uUsage);
----------------------------------------------------
BITMAPINFO bmi = new BITMAPINFO();
bmi.bmiHeader.biSize = 60;
bmi.bmiHeader.biBitCount = 0;
IntPtr hScreenDC = CreateDC("DISPLAY",null,null,IntPtr.Zero);
IntPtr hMemDC = CreateCompatibleDC(hScreenDC);
IntPtr hBitmap = CreateCompatibleBitmap(hScreenDC,800,600);
byte[] lpvBits = null;
int mResult = GetDIBits(hMemDC,hBitmap,0,1,out lpvBits,ref bmi,0);
if( mResult != 0)
MessageBox.Show("Success");
else
MessageBox.Show("Failure");
--------------------------------
the code above is to invoke GetDIBits().The MSDN says if lpvBits is null, bmi should be filled with DC and bitmap Info and mResult should return Non-Zero.
However the mResult is always Zero. How to solve this problem?
|
|
|
|
|
I dunno, but I do recall having no success with this function. Create a DIBSection instead, or better yet, just create a Bitmap and forget all this DLLImport stuff. Why do you need it ?
Christian
I have drunk the cool-aid and found it wan and bitter. - Chris Maunder
|
|
|
|
|
Try declaring your structs like below or even better use a managed equivalent of GetDIBits, which is Bitmap.LockBits
<code>
IntPtr hBitmap = CreateCompatibleBitmap(hScreen, 800, 600);
Bitmap bitmap = Bitmap.FromHbitmap(hBitmap);
BitmapData bData = bitmap.LockBits(new Rectangle(0,0,bitmap.Width,bitmap.Height), ImageLockMode.ReadWrite, bitmap.PixelFormat);
or as I said above try to declare your structs like this if you absolutely must stick to GetDIBits
[StructLayout(LayoutKind.Sequential)]
public class BITMAPINFOHEADER
{
public uint biSize;
public long biWidth;
public long biHeight;
public uint biPlanes;
public uint biBitCount;
public uint biCompression;
public uint biSizeImage;
public long biXPelsPerMeter;
public long biYPelsPerMeter;
public uint biClrUsed;
public uint biClrImportant;
public BITMAPINFOHEADER()
{
biSize = Marshal.SizeOf(this);
}
}
[StructLayout(LayoutKind.Sequential)]
public class RGBQUAD
{
public byte rgbBlue;
public byte rgbGreen;
public byte rgbRed;
public byte rgbReserved;
}
[StructLayout(LayoutKind.Sequential)]
public class BITMAPINFO
{
public BITMAPINFOHEADER bmiHeader;
public RGBQUAD [] bmiColors;
public BITMAPINFO()
{
bmiHeader = new BITMAPINFOHEADER();
bmiColors = new RGBQUAD[1];
}
}
|
|
|
|
|
thanks for your suggestions.
i choose GetDIBits function for i need to get bits info from hBitmap or hDC and to transfer them on the net.
i think transfer bits quicker than this way: get image first and convert into bits,then to send.
but i do have a subsequent problem : the size may be too large.
|
|
|
|
|
You realize there's much easier ways that don't require unmanaged functions? If you're using a TcpClient or some other connection, just get the NetworkStream and write your Bitmap to the stream. Simple. If you want to convert it first (a waste of time), then use either write to a memory stream and then send the bytes, or use the ImageConverter like so:
ImageConverter converter = TypeDescriptor.GetConverter(typeof(Image));
byte[] buffer = (byte[])converter.ConvertTo(image, typeof(byte[])); You really should read the class library documentation in the .NET Framework SDK. There are plenty of ways to do this using only managed code, and a heck of a lot easier as well.
Even if you wanted to get the DIB bits, just use Bitmap.LockBits as someone else mentioned. There is absolutely no reason to P/Invoke unmanaged functions.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
there is the reason to use GetDIBBits. Exactly for network.
Gdiplus doesn't invert bitmap content during BitBlt, fo example.
|
|
|
|
|
I am writing my first 'real' C# control. It's a taskbar that can be positioned to Top/Bottom/Left/Right. What I need to know is which event do I need to use to position it to the bottom when it's initially created.
I tried putting the code in the constructor but you cannot get the parent's properties until after creation.
Can someone please point me in the right direction?
Former VB programmer learning C#. 
Thank you
No comment, Mr. Senator<pre>
|
|
|
|
|
You mean docked to a container, like a Form? See the Dock property, which can be set in the constructor.
Also, you can support initialization after instantiation by implementing the ISupportInitialize interface. The VS.NET designer will automatically call the BeginInit method after instantiating your control, and will call EndInit when done in the InitializeComponent call (you can do this yourself, too - I'm just telling you how VS.NET handles controls that implement this interface).
This way, in your implementation of the EndInit interface, you should have a valid Parent reference (so long as your control was added to the parent's Controls collection property) and can do what you need to. Implementing this interface is a great way to suport initialization of your control in steps.
PS: You could do this using your own implementation without implementing the interface, but VS.NET won't care. Implementing the ISupportInitialize interface is a good way to add designer support for your control. There are other designer-oriented things you can do, which are handy for a lot of programmers. Read Enhancing Design-Time Support[^] in the .NET Framework SDK for more information.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
Thank you Heath this was extremely helpful.
No comment, Mr. Senator<pre>
|
|
|
|
|
Take a look at this:C# does Shell, Part 3[^]
That is really helpful.
abcdabcdabcdabcda
Don't forget, that's Persian Gulf not Arabian gulf!
Why do we close our eyes, when we dream?, When we cry?, When we imagine?, When we kiss?, Its because the most beautiful things in the world are unseen
Murphy:
Click Here![^]
I'm thirsty like sun, more landless than wind...
|
|
|
|
|
Hi all hope all are good
i make a project which i use a neural network iin it so i need to export a DLL file from the nero solution and link it to the C# need help i just found to link nero soultion with C++ 6
hope anyone can help me
thanks in advance
Gego
|
|
|
|
|
You mean you want to P/Invoke all the exported functions? Read Consuming Unmanaged DLL Functions[^] and Marshaling Data with Platform Invoke[^] in the .NET Framework SDK to familiarize yourself with P/Invoke.
Also, we can't help you if you don't provide specifics. If you have problems declaring a managed method to P/Invoke an unmanaged function, that's something we could help you with. You need to at least learn and try to P/Invoke the functions needed from this nero DLL you're talking about.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
Hi Thanks alot for ur replay
but the problem is the nero solution pacakge make a train and test and it can generate a DLL but this DLL is supported by c++ 6 or pervious only i wanna to know if there is a way to link this DLL with C# or if there is a way or an update which make the nero solution generate a DLL file which allow to be linked with an application by C#
thanks alot
byebye for now
Gego
|
|
|
|
|
There is no linking as you think of it in terms of C/C++. The DLL must export functions (either C-style or C++-style) and the DllImportAttribute is used to configure the metadata necessary for the CLR to P/Invoke those calls. Read that link I sent you for more information.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
I am working on a new project.
Basically, I want to implement a Window Form that mimics Internet Explorer.
So, it would consist of two parts.
A Window Shell with a browser capabilties, and the menu will be like a window explorer file-structure style (tree-like structure). And when clicked on the menu, it will call some aspx page (rendered inside the app).
Any hints welcomed.
I would like to know what class to use for those 2 components. Thanks.
Stanley
|
|
|
|
|
There are many articles on Windows Explorer-like interfaces here on CodeProject. I suggest you do a search.
As for Internet Explorer, you need to right-click on your toolbox and customize it. Click on the COM tag and find the "Microsoft Web Browser" or something like that (shdocvw.dll). When you add that to your toolbox and then to your form, two interop assemblies are created: Interop.SHDocVw.dll (contains the interfaces for the WebBrowser control) and AxInterop.AxSHDocVw.dll, which contains the AxHost-derived control you can put on your form. You can use these two together, and there are also plenty of articles about this here on CodeProject. Just use the Navigate or Navigate2 methods (the latter is recommended) to browser to the URL of your ASP.NET page.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
I have the following situation: I serialize an object, let's say ob, and later on I deserialize it and when I try to do this I get an exeption that tells me the following additional information: The constructor to deserialize an object of type ob.subOb was not found.
subOb being another object contained in the main object ob.
How do I have to do the Serialization in this case to get it right?
Thanks for you help.
Best regards,
Cristina
|
|
|
|
|
A type must have either a default constructor (no params) or a constructor that uses the following signature if you implement ISerializable:
access-modifier classname(SerializationInfo info, StreamingContext context)
{
}This is documented in the ISerializable interface documentation in the .NET Framework SDK. Note that you do not have to implement ISerializable for your class to be serializable, only to attribute it with the SerializableAttribute. Implement the interface when you want more control over what gets serialized (the default is all private and public fields).
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
I'm posting this with the risk of Heath getting angry at me because for this one instance I'm not using the parameters in the dataAdapter...not because I like the old way of constructing a long select command, but because I don't know how to use the parameters in this circumstance. I am querying a database, no big deal. But, there are like 7 or 8 different "filter" parameters the user may choose from...and they can also choose to not use any of them. I didn't know how to tell the adapter to ignore that particular parameter, so I resorted to constructing my own select command. However (and Heath will probably say I told you so  ) two of these parameters are dates...I am trying to search BETWEEN Date1 AND Date2. This is giving me some really strange results though. First of all, I have to set Date1 all the way to the day before if I hope to get the correct results. Also, sometimes a perfectly good date range will return nothing, whereas a ridiculous range that hasn't even happened yet, will return rows with dates that don't fall anywhere in between my specified range. I'm sort of confused by it, so if anybody has faced this issue before, I'd like to know how it was solved....or, if I can somehow "turn-off" parameters at run time, or if I can see a small example, one or two lines is all, of how to create a parameter to the adapter at run time (peferrably a BETWEEN AND parameter), I'd be much obliged. And Heath, I know you get really frustrated when people don't use the adapter parameters, cause that's what they are there for, sorry about that.
|
|
|
|
|
If you post your SELECT statement, it'll make it easier to help spot the problem.
Michael
CP Blog [^]
|
|
|
|
|
Putting pound signs around the Date like Heath suggested made my query a little better...I no longer have to subtract a day from Time1 to get the correct results. But here is the strange result I'm getting:
A row with a date column of 5/4/2004 is being selected when the date value of Time2 is 5/11/2004 and Time1 is anything from 5/4/2004 to 5/10/2004, but it's not selecting my row when Time1 is before 5/4/2004, and it should. Here is the statement I'm using to select my rows. I hope you can find something, because I sure can't:
string MySQLText = "SELECT * FROM Invoices";<br />
<br />
DateTime Time1 = new DateTime(dateTimePicker1.Value.Year, dateTimePicker1.Value.Month, dateTimePicker1.Value.Day, 0, 0, 0);<br />
<br />
DateTime Time2 = new DateTime(dateTimePicker2.Value.Year, dateTimePicker2.Value.Month, dateTimePicker2.Value.Day, 23, 59, 59);<br />
<br />
MySQLText += " WHERE (OrderDate BETWEEN #" + Time1.ToString() + "# AND #" + Time2.ToString() + "#)";<br />
<br />
oleDbSelectCommand1.CommandText = MySQLText;<br />
oleDbDataAdapter11.Fill( MyDataset );
|
|
|
|
|
I won't badger you this time, but I still suggest you try it. Once you do, I suspect you'll never turn back. 
Dates in SQL Server are single-quoted like strings. When referring to Date fields, SQL Server knows what to do. For Access (and some other's I've seen, but don't remember) you encase them in pounds (or hashes - #). If you don't, they will be treated like strings (IIRC) so you won't get the result you'd expect.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
Even with the pound signs, the adapter is treating the dates as strings. It is acting like 5/11/04 should go BEFORE 5/4/04. If using the parameters will fix this, I'll change to them as long as I can add them to the adapter programmatically, because in truth I would prefer to use the parameters...I just didn't know how in this situation. What would you suggest? Thank
|
|
|
|
|
Trust me - using parameters is so much better. You can add them programmatically, as there is no other way!
For example (and I'm assuming you're using an OleDbCommand since you're using # signs):
OleDbCommand cmd = oleDbConnection.CreateCommand();
cmd.CommandText = "SELECT * FROM MyTable WHERE DateCol BETWEEN ? AND ?";
cmd.Parameters.Add("StartDate", OleDbType.DBDate).Value = DateTime.Parse("5/4/04");
cmd.Parameters.Add("EndDate", OleDbType.DBDate).Value = DateTime.Parse("5/11/04");
OleDbDataReader reader = null;
try
{
oleDbConnection.Open();
reader = cmd.ExecuteReader();
}
catch (Exception e)
{
Console.Error.WriteLine(e.Message);
}
finally
{
if (reader != null) reader.Close();
oleDbConnection.Close();
}Of course, you could use this command with an OleDbDataAdapter as well - this is just an example.
Still, though it is unusual that it's treating it as a string. You're not using quotes and # signs, are you?
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
I'll give this a try and see if it makes a difference. And no, I just have the hash signs, not the single quotes. The message I replied after the other person's post is a direct copy and paste.
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
