CA1043: Use integral or string argument for indexers
Note
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| Item | Value |
|---|---|
| TypeName | UseIntegralOrStringArgumentForIndexers |
| CheckId | CA1043 |
| Category | Microsoft.Design |
| Breaking Change | Breaking |
Cause
A public or protected type contains a public or protected indexer that uses an index type other than System.Int32, System.Int64, System.Object, or System.String.
Rule Description
Indexers, that is, indexed properties, should use integer or string types for the index. These types are typically used for indexing data structures and increase the usability of the library. Use of the Object type should be restricted to those cases where the specific integer or string type cannot be specified at design time. If the design requires other types for the index, reconsider whether the type represents a logical data store. If it does not represent a logical data store, use a method.
How to Fix Violations
To fix a violation of this rule, change the index to an integer or string type, or use a method instead of the indexer.
When to Suppress Warnings
Suppress a warning from this rule only after carefully considering the need for the nonstandard indexer.
Example
The following example shows an indexer that uses an Int32 index.
using namespace System;
namespace DesignLibrary
{
public ref class Months
{
array<String^>^ month;
public:
property String^ default[int]
{
String^ get(int index)
{
return month[index];
}
void set(int index, String^ value)
{
month[index] = value;
}
}
Months()
{
month = gcnew array<String^>(12);
month[0] = "Jan";
month[1] = "Feb";
//...;
}
};
}
using System;
namespace DesignLibrary
{
public class Months
{
string[] month = new string[] {"Jan", "Feb", "..."};
public string this[int index]
{
get
{
return month[index];
}
}
}
}
Imports System
Namespace DesignLibrary
Public Class Months
Private month() As String = {"Jan", "Feb", "..."}
Default ReadOnly Property Item(index As Integer) As String
Get
Return month(index)
End Get
End Property
End Class
End Namespace