CodeDefaultValueExpression Class
Represents a reference to a default value.
System.CodeDom.CodeObject
System.CodeDom.CodeExpression
System.CodeDom.CodeDefaultValueExpression
Assembly: System (in System.dll)
The CodeDefaultValueExpression type exposes the following members.
| Name | Description | |
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CodeDefaultValueExpression() | Initializes a new instance of the CodeDefaultValueExpression class. |
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CodeDefaultValueExpression(CodeTypeReference) | Initializes a new instance of the CodeDefaultValueExpression class using the specified code type reference. |
| Name | Description | |
|---|---|---|
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Type | Gets or sets the data type reference for a default value. |
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UserData | Gets the user-definable data for the current object. (Inherited from CodeObject.) |
| Name | Description | |
|---|---|---|
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Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
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Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
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GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
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GetType | Gets the Type of the current instance. (Inherited from Object.) |
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MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
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ToString | Returns a string that represents the current object. (Inherited from Object.) |
A CodeDefaultValueExpression can be used to represent a reference to a default value.
The Type property specifies the reference to the value type. The CodeDefaultValueExpression class is used in the generation of generics-based code. For more information on generics, see Generics in the .NET Framework Class Library (C# Programming Guide). The following code steps are provided in this section to further describe the use of the CodeDefaultValueExpression class to add a new default value to a code graph.
The code in part 1 is part of a larger example provided for the CodeTypeParameter class. This code, when run through the C# code generator, results in the C# code that appears in part 2. When this code is called in the statement in part 3, the result is the output shown in part 4.
// Part 1: Code to create a generic Print method.
CodeMemberMethod printMethod = new CodeMemberMethod();
CodeTypeParameter sType = new CodeTypeParameter("S");
sType.HasConstructorConstraint = true;
CodeTypeParameter tType = new CodeTypeParameter("T");
sType.HasConstructorConstraint = true;
printMethod.Name = "Print";
printMethod.TypeParameters.Add(sType);
printMethod.TypeParameters.Add(tType);
printMethod.Statements.Add(ConsoleWriteLineStatement(
new CodeDefaultValueExpression(new CodeTypeReference("T"))));
printMethod.Statements.Add(ConsoleWriteLineStatement(
new CodeDefaultValueExpression(new CodeTypeReference("S"))));
// Part 2: Code generated by code in part 1.
public virtual void Print<S, T>()
where S : new()
{
Console.WriteLine(default(T));
Console.WriteLine(default(S));
}
// Part 3: Call to the generated method. dict.Print<System.Decimal, int>();
// Part 4: Output of the generated method. 0 0
The following code example shows the use of the CodeDefaultValueExpression to create default values for decimal and integer parameters. This example is part of a larger example provided for the CodeTypeParameter class.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
