Assembly.CreateInstance Method (String) not work for System.Windows object

Question

I have one dll (System.Windows). And i am trying to create TextBlock object. but CreateInstance throw error. below i added sample code and exception.

Code Sample....

 try
            {

                System.Reflection.Assembly extAssembly;
                Object objExtAssembly;
                Type tpExtAssembly;
                extAssembly = System.Reflection.Assembly.LoadFrom("dllPath");
                tpExtAssembly = extAssembly.GetType("System.Windows.Controls.TextBlock");

                //    opt1>>

                objExtAssembly = (object)Activator.CreateInstance(tpExtAssembly);

                //    opt2>>

                objExtAssembly = extAssembly.CreateInstance(tpExtAssembly.Namespace + "." + tpExtAssembly.Name);
            }
            catch (Exception ex)
            {
               MessageBox.Show(ex.Message );
            }

If i am using other .net dll than its works fine. If i am doing wrong than let me know

Thanx.....

-----------  Error in Code "objExtAssembly = extAssembly.CreateInstance(tpExtAssembly.Namespace + "." + tpExtAssembly.Name);"

System.Reflection.TargetInvocationException was caught
  HResult=-2146232828
  Message=Exception has been thrown by the target of an invocation.
  Source=mscorlib
  StackTrace:
       at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck)
       at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache)
       at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache)
       at System.Activator.CreateInstance(Type type, Boolean nonPublic)
       at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
       at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
       at System.Reflection.Assembly.CreateInstance(String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
       at System.Reflection.Assembly.CreateInstance(String typeName)
       at SilverlightClassLibrary1.Class1.CallTimer() in D:\My Documents\Visual Studio 2010\Projects\loadObjectTest\SilverlightClassLibrary1\Class1.cs:line 32
  InnerException: System.TypeInitializationException
       HResult=-2146233036
       Message=The type initializer for 'MS.Internal.JoltHelper' threw an exception.
       Source=System.Windows
       TypeName=MS.Internal.JoltHelper
       StackTrace:
            at MS.Internal.JoltHelper.get_ThreadID()
            at MS.Internal.XcpImports.CheckThread()
            at MS.Internal.ManagedPeerHelper.SetupManagedPeer(IManagedPeerBase managedPeer, NativeObjectSafeHandle& nativeSafeHandle, UInt32 nativeTypeIndex, IntPtr constructDO, Nullable`1 isCustomType, Nullable`1 forceStrong)
            at System.Windows.DependencyObject..ctor(UInt32 nativeTypeIndex, IntPtr constructDO)
            at System.Windows.DependencyObject..ctor(UInt32 nativeTypeIndex)
            at System.Windows.UIElement..ctor(UInt32 nKnownTypeIndex)
            at System.Windows.FrameworkElement..ctor(UInt32 nKnownTypeIndex)
            at System.Windows.Controls.TextBlock..ctor()
       InnerException: System.IO.FileNotFoundException
            HResult=-2147024894
            Message=Could not load file or assembly 'System.Net, Version=5.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' or one of its dependencies. The system cannot find the file specified.
            Source=System.Windows
            FileName=System.Net, Version=5.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e
            FusionLog==== Pre-bind state information ===
LOG: User = AUTOMATION\gaurang.patel
LOG: DisplayName = System.Net, Version=5.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e
 (Fully-specified)
LOG: Appbase = file:///D:/My Documents/Visual Studio 2010/Projects/loadObjectTest/loadObjectTest/bin/Debug/
LOG: Initial PrivatePath = NULL
Calling assembly : System.Windows, Version=5.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e.
===
LOG: This bind starts in default load context.
LOG: No application configuration file found.
LOG: Using host configuration file:
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Post-policy reference: System.Net, Version=5.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e
LOG: Attempting download of new URL file:///D:/My Documents/Visual Studio 2010/Projects/loadObjectTest/loadObjectTest/bin/Debug/System.Net.DLL.
LOG: Attempting download of new URL file:///D:/My Documents/Visual Studio 2010/Projects/loadObjectTest/loadObjectTest/bin/Debug/System.Net/System.Net.DLL.
LOG: Attempting download of new URL file:///D:/My Documents/Visual Studio 2010/Projects/loadObjectTest/loadObjectTest/bin/Debug/System.Net.EXE.
LOG: Attempting download of new URL file:///D:/My Documents/Visual Studio 2010/Projects/loadObjectTest/loadObjectTest/bin/Debug/System.Net/System.Net.EXE.

            StackTrace:
                 at MS.Internal.JoltHelper..cctor()
            InnerException:

------------

Answer 1

Hi,

first you should think about the namespaces you are using. It is recommend to use your own namespace-names and not use namespaces of others for your own classes (so no System.*).

In general the core problem seems to be:
Could not load file or assembly 'System.Net, Version=5.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' or one of its dependencies. The system cannot find the file specified.

So maybe your System.Windows DLL has a reference to System.Net and you simply didn't provide that DLL?

With kind regards,

Konrad