Answer:   There are two types of indexes in .Net:
Clustered index and non-clustered index

Answer:   .NET supports two types of indexes:

1. Clustered Index - A B-Tree (computed) clustered index is the index that will arrange the rows physically in the memory in sorted order.
An advantage of a clustered index is that searching for a range of values will be fast. A clustered index is internally maintained using a B-Tree data structure leaf node of B-Tree of clustered index will contain the table data; you can create only one clustered index for a table.

2. Non-clustered Index - A non-clustered index is an index that will not arrange the rows physically in the memory in sorted order.
An advantage of a non-clustered index is searching for the values that are in a range will be fast.
You can create a maximum of 999 non-clustered indexes on a table, which is 254 up to SQL Server 2005.
A non-clustered index is also maintained in a B-Tree data structure but leaf nodes of a B-Tree of non-clustered index contains the pointers to the pages that contain the table data and not the table data directly.