Overload that takes a single search factor and returns a match following this order:
1. With multiple matches, active identity if one exists, or else first match.
2. When there is a single match, the match.
3. When there is no match, null.
Read identity is based on search factor. First read from IMS store, and then optionally read from source like Active Directory.
Namespace:  Microsoft.TeamFoundation.Framework.Client
Assembly:  Microsoft.TeamFoundation.Client (in Microsoft.TeamFoundation.Client.dll)
Syntax
'Declaration
Function ReadIdentity ( _
    searchFactor As IdentitySearchFactor, _
    searchFactorValue As String, _
    queryMembership As MembershipQuery, _
    readOptions As ReadIdentityOptions, _
    propertyNameFilters As IEnumerable(Of String), _
    propertyScope As IdentityPropertyScope _
) As TeamFoundationIdentity
TeamFoundationIdentity ReadIdentity(
    IdentitySearchFactor searchFactor,
    string searchFactorValue,
    MembershipQuery queryMembership,
    ReadIdentityOptions readOptions,
    IEnumerable<string> propertyNameFilters,
    IdentityPropertyScope propertyScope
)
TeamFoundationIdentity^ ReadIdentity(
    IdentitySearchFactor searchFactor, 
    String^ searchFactorValue, 
    MembershipQuery queryMembership, 
    ReadIdentityOptions readOptions, 
    IEnumerable<String^>^ propertyNameFilters, 
    IdentityPropertyScope propertyScope
)
abstract ReadIdentity : 
        searchFactor:IdentitySearchFactor * 
        searchFactorValue:string * 
        queryMembership:MembershipQuery * 
        readOptions:ReadIdentityOptions * 
        propertyNameFilters:IEnumerable<string> * 
        propertyScope:IdentityPropertyScope -> TeamFoundationIdentity
function ReadIdentity(
    searchFactor : IdentitySearchFactor, 
    searchFactorValue : String, 
    queryMembership : MembershipQuery, 
    readOptions : ReadIdentityOptions, 
    propertyNameFilters : IEnumerable<String>, 
    propertyScope : IdentityPropertyScope
) : TeamFoundationIdentity
Parameters
- searchFactor 
 Type: Microsoft.TeamFoundation.Framework.Common.IdentitySearchFactor- How search is specified, for example by account name, and so on. 
- searchFactorValue 
 Type: System.String- Actual search string, such as account name. 
- queryMembership 
 Type: Microsoft.TeamFoundation.Framework.Common.MembershipQuery- None, direct or expanded membership information. 
- readOptions 
 Type: Microsoft.TeamFoundation.Framework.Common.ReadIdentityOptions- Read options, such as reading from source. 
- propertyNameFilters
 Type: System.Collections.Generic.IEnumerable<String>
- propertyScope
 Type: Microsoft.TeamFoundation.Framework.Common.IdentityPropertyScope
Return Value
Type: Microsoft.TeamFoundation.Framework.Client.TeamFoundationIdentity
Array of matching identities.
.NET Framework Security
- Full trust for the immediate caller. This member cannot be used by partially trusted code. For more information, see Using Libraries from Partially Trusted Code.