AboutMyDot.Net

Last week i needed to compile and run scripts at runtime. The idea was to add code snippets into a DB and load and execute them at runtime. My first idea was to write a scripting language but it was an hard work and i had no time for this.
Searching around i found a very interesting thing about the Framework. It’s possible to load, compile and run .Net code from script file or simple string. Everything happens in memory so you don’t need to generate an output file

Here is the solution:

Needed:
Imports System
Imports System.Reflection
Imports System.Reflection.Emit

Assume we have a TextBox named TextBox1 where we’ll write the source code we want to compile and run on the fly.

 Try
    If TextBox1.Text.Trim <> "" Then
        Dim VBP As New VBCodeProvider
        Dim CVB As System.CodeDom.Compiler.ICodeCompiler
        CVB = VBP.CreateCompiler
        Dim PM As New System.CodeDom.Compiler.CompilerParameters
        PM.GenerateInMemory = True
        '  PM.GenerateExecutable = True
        PM.OutputAssembly = "Generated.dll"
        PM.MainClass = "ClassMain"
        PM.IncludeDebugInformation = True
 
        Dim ASM As System.Reflection.Assembly
        For Each ASM In AppDomain.CurrentDomain.GetAssemblies()
            PM.ReferencedAssemblies.Add(ASM.Location)
        Next

        'Get compilation results
        Dim Results As System.CodeDom.Compiler.CompilerResults
        Results = CVB.CompileAssemblyFromSource(PM, TextBox1.Text)
 
        'Show possible compilation errors
        Dim Err As System.CodeDom.Compiler.CompilerError
        For Each err In Results.Errors
            ListBox1.Items.Add("Error N. " & err.ErrorNumber &_
            " Message: " & err.ErrorText & " Line " & err.Line)
        Next
 
        'Use the compiled assembly
        Dim RunObj As New Object
        Dim vArgs() As Object
 
        RunObj = Results.CompiledAssembly.CreateInstance(
        	 "Generated.ClassMain", False,
        	 Reflection.BindingFlags.CreateInstance, Nothing,
        	 vArgs, Nothing, Nothing)

        If Not RunObj Is Nothing Then
            RunObj.Esegui()
        Else
            MsgBox.Show("Compile Error")
        End If
 
    Else
        MsgBox.Show("Write VB.Net code to compile")
    End If
Catch err As Exception
    MsgBox.Show(err.Message & " " & err.StackTrace)
End Try

Download this code: RuntimeCode.vb.txt

Here is a sample vb file that you can load and compile at runtime

Imports System.Windows.Forms
Imports Microsoft.VisualBasic
 
namespace Generated
   public class ClassMain
 
       public sub Esegui()
           messagebox.show("Ciao come va?")
       end sub
 
   end class
end namespace

Download this code: RuntimeCodeTest.vb.txt

I hope it could be useful for your tasks

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TAGS: Asp.net, dotnet, code snippet, seo, search engine optimization, visual studio.net, sample code, c#, vb.net

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