ParameterBuilder Class
Creates or associates parameter information.
Namespace: System.Reflection.Emit
Assembly: mscorlib (in mscorlib.dll)
The ParameterBuilder type exposes the following members.
| Name | Description | |
|---|---|---|
![]() ![]() | Attributes | Gets the attributes for this parameter. |
![]() ![]() | IsIn | Gets a value that indicates whether this is an input parameter. |
![]() ![]() | IsOptional | Gets a value that indicates whether this parameter is optional. |
![]() ![]() | IsOut | Gets a value that indicates whether this parameter is an output parameter. |
![]() ![]() | Name | Gets the name of this parameter. |
![]() ![]() | Position | Gets the signature position for this parameter. |
| Name | Description | |
|---|---|---|
![]() ![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() ![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.) |
![]() ![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetToken | Gets the token for this parameter. |
![]() ![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() ![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() ![]() | SetConstant | Sets the default value of the parameter. |
![]() | SetCustomAttribute(CustomAttributeBuilder) | Set a custom attribute using a custom attribute builder. |
![]() ![]() | SetCustomAttribute(ConstructorInfo, Byte()) | Security Critical. Set a custom attribute using a specified custom attribute blob. |
![]() ![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
Parameter attributes need to consistent with the method signature. If you specify Out attributes for a parameter, you should ensure that the type of that method parameter is a ByRef type.
Some ParameterBuilder attributes require that you call DefineMethod with viable parameters in order for the Microsoft intermediate language (MSIL) to work correctly at runtime. For example, if you define a ParameterBuilder with ParameterAttributes.Out for parameter 1 of a MethodBuilder, then parameter 1 of MethodBuilder must be a reference such as Type.GetType("System.String&"), rather than Type.GetType("System.String").
The following example demonstrates how to create a dynamic method with a parameter passed by reference using ParameterBuilder.
Note: |
|---|
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control. |
Imports System.Threading Imports System.Reflection Imports System.Reflection.Emit _ Class Example Public Shared Function BuildCustomerDataType() As Type Dim myDomain As AppDomain = Thread.GetDomain() Dim myAsmName As New AssemblyName() myAsmName.Name = "MyDynamicAssembly" Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAsmName, _ AssemblyBuilderAccess.Run) Dim myModBuilder As ModuleBuilder = myAsmBuilder.DefineDynamicModule("MyMod") Dim myTypeBuilder As TypeBuilder = myModBuilder.DefineType("CustomerData", TypeAttributes.Public) Dim customerNameBldr As FieldBuilder = myTypeBuilder.DefineField("customerName", _ GetType(String), _ FieldAttributes.Private) Dim acctIDBldr As FieldBuilder = myTypeBuilder.DefineField("acctID", _ GetType(String), _ FieldAttributes.Private) Dim balanceAmtBldr As FieldBuilder = myTypeBuilder.DefineField("balanceAmt", _ GetType(Double), _ FieldAttributes.Private) Dim myCtorBuilder As ConstructorBuilder = myTypeBuilder.DefineConstructor(MethodAttributes.Public, _ CallingConventions.HasThis, _ New Type() {GetType(String), _ GetType(String), _ GetType(Double)}) Dim ctorIL As ILGenerator = myCtorBuilder.GetILGenerator() Dim objType As Type = Type.GetType("System.Object") Dim objCtor As ConstructorInfo = objType.GetConstructor(New Type() {}) ctorIL.Emit(OpCodes.Ldarg_0) ctorIL.Emit(OpCodes.Call, objCtor) ctorIL.Emit(OpCodes.Ldarg_0) ctorIL.Emit(OpCodes.Ldarg_1) ctorIL.Emit(OpCodes.Stfld, customerNameBldr) ctorIL.Emit(OpCodes.Ldarg_0) ctorIL.Emit(OpCodes.Ldarg_2) ctorIL.Emit(OpCodes.Stfld, acctIDBldr) ctorIL.Emit(OpCodes.Ldarg_0) ctorIL.Emit(OpCodes.Ldarg_3) ctorIL.Emit(OpCodes.Stfld, balanceAmtBldr) ctorIL.Emit(OpCodes.Ret) ' This method will take an amount from a static pool and add it to the balance. ' Note that we are passing the first parameter, fundsPool, by reference. Therefore, ' we need to inform the MethodBuilder to expect a ref, by declaring the first ' parameter's type to be System.Double& (a reference to a double). Dim myMthdBuilder As MethodBuilder = myTypeBuilder.DefineMethod("AddFundsFromPool", _ MethodAttributes.Public, _ GetType(Double), _ New Type() {Type.GetType("System.Double&"), _ GetType(Double)}) Dim poolRefBuilder As ParameterBuilder = myMthdBuilder.DefineParameter(1, _ ParameterAttributes.Out, "fundsPool") Dim amountFromPoolBuilder As ParameterBuilder = myMthdBuilder.DefineParameter(2, _ ParameterAttributes.In, "amountFromPool") Dim mthdIL As ILGenerator = myMthdBuilder.GetILGenerator() mthdIL.Emit(OpCodes.Ldarg_1) mthdIL.Emit(OpCodes.Ldarg_1) mthdIL.Emit(OpCodes.Ldind_R8) mthdIL.Emit(OpCodes.Ldarg_2) mthdIL.Emit(OpCodes.Sub) mthdIL.Emit(OpCodes.Stind_R8) mthdIL.Emit(OpCodes.Ldarg_0) mthdIL.Emit(OpCodes.Ldarg_0) mthdIL.Emit(OpCodes.Ldfld, balanceAmtBldr) mthdIL.Emit(OpCodes.Ldarg_2) mthdIL.Emit(OpCodes.Add) mthdIL.Emit(OpCodes.Stfld, balanceAmtBldr) mthdIL.Emit(OpCodes.Ldarg_0) mthdIL.Emit(OpCodes.Ldfld, balanceAmtBldr) mthdIL.Emit(OpCodes.Ret) Return myTypeBuilder.CreateType() End Function 'BuildCustomerDataType Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock) Dim custType As Type = Nothing Dim custObj As Object = Nothing Dim custArgTypes() As Type = {GetType(String), GetType(String), GetType(Double)} ' Call the method to build our dynamic class. custType = BuildCustomerDataType() outputBlock.Text &= "---" & vbCrLf Dim myCustCtor As ConstructorInfo = custType.GetConstructor(custArgTypes) Dim initialBalance As Double = 100.0 custObj = myCustCtor.Invoke(New Object() {"Joe Consumer", "5678-XYZ", initialBalance}) Dim myMemberInfo As MemberInfo() = custType.GetMember("AddFundsFromPool") Dim thePool As Double = 1000.0 outputBlock.Text &= String.Format("The pool is currently ${0}", thePool) & vbCrLf outputBlock.Text &= String.Format("The original balance of the account instance is ${0}", initialBalance) & vbCrLf Dim amountFromPool As Double = 50.0 outputBlock.Text &= String.Format("The amount to be subtracted from the pool and added " & _ "to the account is ${0}", amountFromPool) & vbCrLf outputBlock.Text &= "---" & vbCrLf outputBlock.Text &= String.Format("Calling {0} ...", myMemberInfo(0).ToString()) & vbCrLf outputBlock.Text &= "---" & vbCrLf Dim passMe() As Object = {thePool, amountFromPool} outputBlock.Text &= String.Format("The new balance in the account instance is ${0}", _ custType.InvokeMember("AddFundsFromPool", _ BindingFlags.InvokeMethod, Nothing, custObj, passMe)) & vbCrLf thePool = CDbl(passMe(0)) outputBlock.Text &= String.Format("The new amount in the pool is ${0}", thePool) & vbCrLf End Sub 'Main End Class 'ParamBuilderDemo
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.




Note: