GUID + DataBind gives exception?

Question

I have the following piece of code:

string ConnString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
string SqlString = "Select * From Memberships WHERE ApplicationId =  @username";
using(SqlConnection conn = new SqlConnection(ConnString)) {
  using(SqlCommand cmd = new SqlCommand(SqlString, conn)) {
    cmd.CommandType = CommandType.Text;
    SqlParameter param = new SqlParameter();
    param.ParameterName = "@username";
    param.Value = UserName2.Text;
    cmd.Parameters.Add(param);
    conn.Open();
    using(SqlDataReader reader = cmd.ExecuteReader()) {
      test.DataSource = reader;
      test.DataBind();
    }
  }
}

In this case the codes breaks on DataBind() with the following error: Conversion failed when converting from a character string to uniqueidentifier. This is caused because I'm using the ApplicationId in my query instead of the UserName. With the UserName all works fine.

I know that the GUID is causing the error, but I don't know why and how to fix it.

score 0 · Accepted Answer · edited May 23 '17 at 11:49

0

What is type of AplicationId in your db? If guid - your problem is comparing string parameter to guid. Cast one of them.

Something like convert(nvarchar(50), ApplicstionID)

See also SQL Server: converting UniqueIdentifier to string in a case statement

edited May 23 '17 at 11:49

Community

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answered Apr 06 '13 at 14:26

evgenyl

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Yes, ApplicationID is a GUID. Can you help me how to cast the value for @username in my query? – MartinH Apr 06 '13 at 14:30
That's it! Thanks for your help. It makes me wondering however, why was the exception being cast at the DataBind() method? – MartinH Apr 06 '13 at 15:35
Because on my understanding, you really fetch the data only on binding. – evgenyl Apr 06 '13 at 18:51
I had a feeling that it would be something like that. Thanks for the help. – MartinH Apr 07 '13 at 11:50

GUID + DataBind gives exception?

1 Answers1