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==There are a few restrictions to conversion operators==

<OL><LI>Either the target type or the source type of the conversion must be a class that you create.</LI><LI>You cannot redefine the conversion from double to int.</LI><LI>You cannot define a conversion to or from Object.</LI><LI>You cannot define both an implicit and an explicit conversion for the same source and target types.</LI><LI>You cannot define a conversion from a base class to a derived class.</LI><LI>You cannot define a conversion from or to an interface.</LI></OL>
(Quote from C# The Complete Reference, Publisher: Osborne/McGraw-Hill, March 8, 2002,
Language: English ISBN-10: 0072134852 ISBN-13: 978-0072134858)
<OL><LI>Here are the other operators that cannot be overloaded. </LI><LI>&&</LI><LI>||</LI><LI>[]</LI><LI>()</LI><LI>new</LI><LI>is</LI><LI>sizeof</LI><LI>typeof</LI><LI>?</LI><LI>-></LI><LI>.</LI><LI>=</LI></OL>
8.4.Conversion Operator Overload
8.4.1.
<A href="/Tutorial/CSharp/0160__Operator-Overload/Therearetwoformsofconversionoperatorsimplicitandexplicit.htm">There are two forms of conversion operators, implicit and explicit</a>
8.4.2.
There are a few restrictions to conversion operators
8.4.3.
<A href="/Tutorial/CSharp/0160__Operator-Overload/UserDefinedConversionsConversionLookup.htm">User-Defined Conversions: Conversion Lookup</a>
8.4.4.
<A href="/Tutorial/CSharp/0160__Operator-Overload/UserDefinedConversions.htm">User-Defined Conversions</a>

==There are two forms of conversion operators, implicit and explicit==

The general form for each is shown here:

<source lang="csharp">public static operator implicit target-type(source-type v) {
return value;
}</source>

==User-Defined Conversions==

<source lang="csharp">using System;
using System.Text;
struct MyType
{
private int value;

public MyType(int value)
{
this.value = value;
}
public static explicit operator MyType(short value){
Console.WriteLine("public static explicit operator MyType(short value)");

return new MyType();
}

public static implicit operator short(MyType myType){
Console.WriteLine("public static implicit operator short(MyType myType)");
return 0;
}

public static implicit operator string(MyType myType){
Console.WriteLine("public static implicit operator string(MyType myType)");
return "String value:";
}
}
class MainClass
{
public static void Main()
{
int s = 12;
MyType numeral = new MyType(s);

s = 165;
numeral = (MyType) s;

Console.WriteLine("as int: {0}", (int)numeral);
Console.WriteLine("as string: {0}", (string)numeral);

int s2 = numeral;
}
}</source>
<pre class=codeResult>public static explicit operator MyType(short value)
public static implicit operator short(MyType myType)
as int: 0
public static implicit operator string(MyType myType)
as string: String value:
public static implicit operator short(MyType myType)</pre>

==User-Defined Conversions: Conversion Lookup==

<source lang="csharp">using System;
public class MyType
{
public static implicit operator YourType(MyType s)
{
Console.WriteLine("conversion here");
return(new YourType());
}
}
public class YourType
{
}
public class YourDerivedType: YourType
{

}
public class Test
{
public static void Main()
{
MyType myType = new MyType();
YourType tb = (YourType) myType;
}
}</source>
<pre class=codeResult>conversion here</pre>

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