developed a web service in asp.net with 2 files service1.asmx & service1.asmx.cs
service1.asmx.cs has 2 methods to get the records from database
i have defined the connectionstring in the service1.asmx.cs file to connect to sqldatabase
but i am not able to provide login creditentails for accesing the sql server 2005 db in service1.asmx.cs file
when i execute the service it gets opened in a browser withthe specified methods
when i try to invoke a method i get login failed

i need to knw how do i pass the login creditentails so that the methods of webservice gets executed & where do i put the credientials


error

System.Data.SqlClient.SqlException: Login failed for user ''. The user is not associated with a trusted SQL Server connection.
at System.Data.SqlClient.SqlInternalConnection.OnErro r(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsPr.ThrowExceptionAndW arning(TdsPrStateObject stateObj)
at System.Data.SqlClient.TdsPr.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsPrStateObject stateObj)
at System.Data.SqlClient.SqlInternalConnectionTds.Com pleteLogin(Boolean enlistOK)
at System.Data.SqlClient.SqlInternalConnectionTds.Att emptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject)
at System.Data.SqlClient.SqlInternalConnectionTds.Log inNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart)
at System.Data.SqlClient.SqlInternalConnectionTds.Ope nLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance)
at System.Data.SqlClient.SqlInternalConnectionTds..ct or(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
at System.Data.SqlClient.SqlConnectionFactory.CreateC onnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection)
at System.Data.ProviderBase.DbConnectionFactory.Creat ePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options)
at System.Data.ProviderBase.DbConnectionPool.CreateOb ject(DbConnection owningObject)
at System.Data.ProviderBase.DbConnectionPool.UserCrea teRequest(DbConnection owningObject)
at System.Data.ProviderBase.DbConnectionPool.GetConne ction(DbConnection owningObject)
at System.Data.ProviderBase.DbConnectionFactory.GetCo nnection(DbConnection owningConnection)
at System.Data.ProviderBase.DbConnectionClosed.OpenCo nnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
at System.Data.SqlClient.SqlConnection.Open()
at WSC.Service1.getCentreNames() in D:\WSC\WSC\Service1.asmx.cs:line 99