Using ctAPI Library in c#

[Vahid.Keykhaey]

Hi, My code is as below:
public void Init() { IntPtr hCTAPI = CTAPI.ctOpen(null, "u1", "1", 2); TestMe(hCTAPI); } [DllImport("ctapi.dll", CallingConvention = CallingConvention.StdCall, SetLastError = true)] public static extern IntPtr ctOpen(string sComputerName, string sUsername, string sPassword, UInt32 nMode); [DllImport("ctapi.dll", CallingConvention = CallingConvention.StdCall, SetLastError = true)] public static extern bool ctTagRead(IntPtr hCTAPI, [MarshalAs(UnmanagedType.LPStr)] string tag, [MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder value, int length); public static void TestMe(IntPtr ip) { var tag = "tag1"; var tagPtr = Marshal.StringToHGlobalAnsi(tag); System.Text.StringBuilder vsl = new StringBuilder(20); bool b = ctTagRead(ip, tag, vsl, 20);//, tagValueItemsPtr); }
bool b is always false. I dont know what to do!

I used GetLastError Function and I found out there is a "No connection could be made because the target machine actively refused it" error. but I am trying to connect to citect on my own computer which has an installed and working citect on it, and in citect.ini [ctapi] remote is set to 1.

 

[Archie]

I do not use Citect software, so I will not be able to help with the answer, but I will at least help make your post easier to read for others that may be able to help. This is the C# code formatted:

 public void Init() {
     IntPtr hCTAPI = CTAPI.ctOpen(null, "u1", "1", 2); TestMe(hCTAPI);
 }
       
 [DllImport("ctapi.dll", CallingConvention = CallingConvention.StdCall, SetLastError = true)]
 public static extern IntPtr ctOpen(string sComputerName, string sUsername, string sPassword, UInt32 nMode);
        
 [DllImport("ctapi.dll", CallingConvention = CallingConvention.StdCall, SetLastError = true)]
 public static extern bool ctTagRead(IntPtr hCTAPI, [MarshalAs(UnmanagedType.LPStr)] string tag,
                        [MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder value, int length);
        
 public static void TestMe(IntPtr ip) { 
     var tag = "tag1";
     var tagPtr = Marshal.StringToHGlobalAnsi(tag);
     System.Text.StringBuilder vsl = new StringBuilder(20);
     bool b = ctTagRead(ip, tag, vsl, 20);
     //, tagValueItemsPtr);
 }

 

[Vahid.Keykhaey]

Thanks

 

[Maximushski]

Open with CtApi

Hi, did you end up getting it to work?

Try setting the first three arguments to ctOpen to null, since these are not needed when connecting to a Citect instance on the same computer.

The CTAPI function reference also recommends that you set the mode argument to 0.

E.g.
hCTAPI = ctOpen(NULL, NULL, NULL, 0);

Also, I believe that .NET uses Unicode strings. Make sure all strings you pass through CTAPI are ANSI or the tag name will be invalid, causing ctTagRead to always return false.

 

[Vahid.Keykhaey]

Hi Maximus,
Nope, It did not work for me.
I Injected a DLL into Citect to do my work. But my antivirus is now suspicious of what I do.
Thanks