I have a problem that is a bit complicated to explain (otherwise I wouldn't have problems with it :) ), but I'll give it a try.
I have an asp.net webapplication and I'm trying to load user controls at runtime from an other project without the original website having a reference to the project/dll containing the usercontrol.
When I know the path of all the needed files (dll etc .. I can make it work) especially for the assembly.loadfile(Path). But now I'm using a virtualpathProvider wich can only provide me with a stream. so I can't use assembly.loadfile(path) anymore, but I have to use Assembly.load(byte[]) . The problem is, when switching to assembly.load(byte[]) i can't compile the ascx files anymore. It gives me this exception:
The 'ReferencedAssemblies' property cannot contain null or empty strings. Parameter name: options
The only difference between the loaded assemblies is that the property Location gives an error. I assume that the location of the assemblies is passed to the builder.
Is there anybody who could provide any idea's on how to solve this? (Other than: write the assembly to a temp folder on the disk)
I was thinking on my own buildprovider or something in this direction, but I'm afraid that I might run in to the same issues.
This seems like the same issue eventually: Supply Assembly to CompilerParameters ReferencedAssemblies from memory and not disk?
Now for a better understanding, and possible helping other people out: the full stacktrace and full source:
full stacktrace
at Microsoft.VisualBasic.VBCodeGenerator.CmdArgsFromParameters(CompilerParameters options)
at Microsoft.VisualBasic.VBCodeGenerator.FromFileBatch(CompilerParameters options, String[] fileNames)
at System.CodeDom.Compiler.CodeCompiler.System.CodeDom.Compiler.ICodeCompiler.CompileAssemblyFromFileBatch(CompilerParameters options, String[] fileNames)
at System.Web.Compilation.AssemblyBuilder.Compile()
at System.Web.Compilation.BuildProvidersCompiler.PerformBuild()
at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath)
at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound)
at System.Web.Compilation.BuildManager.GetCompiledType(VirtualPath virtualPath)
at WebApplication1._Default.CompileAddControl(String path) in E:\Google Drive\Lab\DLLLoading\WebApplication1\Default.aspx.vb:line 29
I have 2 webapplications, a normal one, and one with only ascx(usercontrol) files in it.
Webapplication2:
This contains the usercontrol and nothing else.
ShowTime.ascx
<%@ Control
Language="vb"
AutoEventWireup="false"
CodeBehind="Showtime.ascx.vb"
Inherits="WebApplication2.Showtime,WebApplication2"
%>
<asp:Label ID="lblTime" runat="server"></asp:Label>
Here I added the assembly name to the Inherits value => otherwise the application won't understand that is has to look in a different assembly for the code.
ShowTime.ascx.vb
Public Class Showtime
Inherits System.Web.UI.UserControl
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
lblTime.Text = "Hello world from external :" & Now.ToShortDateString & " - " & Now.ToShortTimeString
End Sub
End Class
That's all that there is needed for this Webapplication.
WebApplication1:
Here is where the magic happens
Global.asax
Imports System.Reflection
Imports System.Web.Hosting
Imports System.IO
Public Class Global_asax
Inherits System.Web.HttpApplication
Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
AddHandler AppDomain.CurrentDomain.AssemblyResolve, AddressOf Global_asax.ResolveEventHandler
End Sub
Public Shared Function ResolveEventHandler(sender As Object, args As System.ResolveEventArgs) As Assembly
Try
If args.Name.StartsWith("WebApplication2") Then
Dim _ret As Assembly
''START OF NOT WORKING CODE
''To make this path work, I added the other application with ascx's as a virtual directory (~/apps/HelloWorld/) in IIS.. (make sure to NOT have a web.config in webapplication2)
Dim _vf As VirtualFile = HostingEnvironment.VirtualPathProvider.GetFile("~/apps/HelloWorld/bin/WebApplication2.dll")
'copy to memorystream so i can use the very handy toArray function (speed of coding)
Using _ms As New MemoryStream, _s As Stream = _vf.Open()
_s.CopyTo(_ms)
_ret = Assembly.Load(_ms.ToArray)
End Using
''END OF NOT WORKING CODE
''START OF WORKING CODE
'Dim _ret As Assembly = Assembly.LoadFile(HostingEnvironment.MapPath("~/apps/HelloWorld/bin/WebApplication2.dll"))
''START OF WORKING CODE
Return _ret
End If
Return Nothing
Catch ex As Exception
'this is a test project so debug.writeline will do..
Debug.WriteLine(ex.ToString)
Return Nothing
End Try
End Function
Default.aspx
This one has this control:
Default.aspx.vb
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Try
CompileAddControl("~/apps/HelloWorld/Showtime.ascx")
Catch ex As Exception
Debug.WriteLine(ex.ToString)
End Try
End Sub
Private Shared m_dict As New Dictionary(Of String, Type)
Public Sub CompileAddControl(path As String)
Try
Dim _t As Type = Nothing
If Not m_dict.TryGetValue(path, _t) Then
_t = BuildManager.GetCompiledType(path)
m_dict.Add(path, _t)
End If
Dim _o As Control = DirectCast(BuildManager.CreateInstanceFromVirtualPath(path, _t), Control)
phControls.Controls.Add(_o)
Catch ex As Exception
phControls.Controls.Add(New LiteralControl(ex.Message))
End Try
End Sub
