What I believe is happening in your application is the following:
When Labview launches, it pulls in the dll of your application, tightly locking it into memory. As such, the file is locked and Visual Studio won't be able to overwrite this file (I have directly seen this behavior in other applications). Since the dll never gets freed until Labview exits, you need to find a way to "trick" Labview into loading a fresh dll every time you re-compile.
Here is what I recommend:
In LabView, instead of loading your dll directly, as suggested by Chris Sterling you'll want to create a "wrapper" dll that will load your specific LabView dll through an interface
By utilizing an interface stored in your wrapper dll you fully decouple the two dlls, which will prevent the wrapper dll from knowing about/locking your primary dll. Later, when you are finished with the debugging, you can directly link the dll to LabView.
Here is roughly how the code should look:
public class LabViewWrapper : IYourCustomClass
{
private IYourCustomClass _labViewClass;
private string labviewPath = "Full Path to labview dll";
public LabViewWrapper()
{
Assembly assembly;
try
{
using (FileStream fs = File.OpenRead(labviewPath))
{
using (MemoryStream ms = new MemoryStream())
{
byte[] buffer = new byte[1024];
int read = 0;
while ((read = fs.Read(buffer, 0, 1024)) > 0)
ms.Write(buffer, 0, read);
assembly = Assembly.Load(ms.ToArray());
ms.Close();
}
fs.Close();
}
Type t = assembly.GetType(IYourCustomClass);
_labViewClass= (IYourCustomClass)Activator.CreateInstance(t);
}
catch
{
// Unable to load dll dynamically
}
}
// Implement all the methods in your interface with something like the following:
/// <summary>
/// Your Custom Method
/// </summary>
public void CustomLabViewMethod()
{
_labViewClass.CustomLabViewMethod();
}
}
By doing it this way, you are loading the dll from memory, and therefore labview never locks your original dll that you compiled. The only real downside with this is that it does make debugging harder, if you want to insert breakpoints, you'll likely need to directly reference the source dll.
Note: One thing I am not sure about, but I believe will "work out" is whether Labview is smart enough to re-construct the object every time it executes your code, or whether it just keeps the same object throughout the session. If it does end up doing the later, you'll need to add code to "reload" the dll from the file system every time you launch your custom widget.
