Error converting data type varchar to uniqueidentifier

[fr2]

There is SQL Server stored procedure with one of the input parameters a uniqueidentifier ...

I tested the sp in SQL Server itself and it works fine ..
However from ASP.NET code when tring to use the sp .. I get the error

Error converting data type varchar to uniqueidentifier

How do I pass the uniqueidentifier (userID) value .. I tried varchar .. but no luck it seems

mDbConn = New SqlConnection(ConnectionString)
mDbConn.Open()

mSqlCmd = New SqlCommand("usp_GetMYsp", mDbConn)
mSqlCmd.CommandType =Data.CommandType.StoredProcedure

mSqlCmd.Parameters.Add("@userID", Data.SqlDbType.VarChar)
mSqlCmd.Parameters("@userID").Value = myVal.ToSTring

mSqlCmd.Parameters.Add("@Field2", Data.SqlDbType.Int)
mSqlCmd.Parameters("@Field2").Value = intEventUserEventRoleID

mSqlDr = mSqlCmd.ExecuteReader()

 

[jbenson001]

try:

mSqlCmd.Parameters.Add("@userID", Data.SqlDbType.[red]UniqueIdentifier[/red])