PropertyInfo.GetIndexParameters Method

Return Value

Type: array<System.Reflection.ParameterInfo[]
An array that contains the parameters for the indexes. If the property is not indexed, the array has 0 (zero) elements.

Imports System.Reflection
Imports System.Collections

' A test class that has some properties.
Public Class MyProperty

   ' Define a simple string property.
   Private myCaption As String = "A Default caption"
   Public Property Caption() As String
      Get
         Return myCaption
      End Get
      Set(ByVal Value As String)
         If myCaption <> Value Then
            myCaption = Value
         End If
      End Set
   End Property

   ' A very limited indexed default property that gets or
   ' sets one of four string values.
   Private strings() As String = {"abc", "def", "ghi", "jkl"}
   Default Public Property Item(ByVal Index As Integer) As String
      Get
         Return strings(Index)
      End Get
      Set(ByVal value As String)
         strings(Index) = value
      End Set
   End Property
End Class

Public Class Example

   Public Shared Function Demo(ByVal outputBlock As System.Windows.Controls.TextBlock) As Integer

      ' Get the type and PropertyInfo.
      Dim t As Type = GetType(MyProperty)
      Dim pi As PropertyInfo = t.GetProperty("Caption")

      ' Get an array containing the parameters (if any).
      Dim params As ParameterInfo() = pi.GetIndexParameters()
      outputBlock.Text &= vbCrLf & t.FullName & "." & pi.Name & _
         " has " & params.GetLength(0) & " parameters." & vbCrLf

      ' Display a property that has parameters.
      pi = t.GetProperty("Item")
      params = pi.GetIndexParameters()
      outputBlock.Text &= t.FullName & "." & pi.Name & _
         " has " & params.GetLength(0) & " parameters." & vbCrLf
      For Each p As ParameterInfo In params
         outputBlock.Text &= "   Parameter: " & p.Name & vbCrLf
      Next

      Return 0
   End Function
End Class

' This example produces the following output:
' MyProperty.Caption has 0 parameters.
' MyProperty.Item has 1 parameters.
'    Parameter: Index

using System;
using System.Reflection;

// A class that contains some properties.
public class MyProperty
{
   // Define a simple string property.
   private string caption = "A Default caption";
   public string Caption
   {
      get { return caption; }
      set
      {
         if (caption != value) { caption = value; }
      }
   }

   // A very limited indexer that gets or sets one of four 
   // strings.
   private string[] strings = { "abc", "def", "ghi", "jkl" };
   public string this[int Index]
   {
      get
      {
         return strings[Index];
      }
      set
      {
         strings[Index] = value;
      }
   }
}

class Example
{
   public static int Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Get the type and PropertyInfo.
      Type t = Type.GetType("MyProperty");
      PropertyInfo pi = t.GetProperty("Caption");

      // Get the public GetIndexParameters method.
      ParameterInfo[] parms = pi.GetIndexParameters();
      outputBlock.Text += "\r\n" + t.FullName + "." + pi.Name
          + " has " + parms.GetLength(0) + " parameters." + "\n";

      // Display a property that has parameters. The default 
      // name of an indexer is "Item".
      pi = t.GetProperty("Item");
      parms = pi.GetIndexParameters();
      outputBlock.Text += t.FullName + "." + pi.Name + " has " +
          parms.GetLength(0) + " parameters." + "\n";
      foreach (ParameterInfo p in parms)
      {
         outputBlock.Text += "   Parameter: " + p.Name + "\n";
      }

      return 0;
   }
}
/*
 This example produces the following output:
 MyProperty.Caption has 0 parameters.
 MyProperty.Item has 1 parameters.
    Parameter: Index
 */