CODEWITHSUNDEEP
c#asp.netgridview
Anthony Knight
Anthony Knight

Reputation: 63

Invalid cast from 'System.String' to 'System.Guid

My page uses a GridView to show all clients to the user after he or she logs in. However I'm trying to get the GridView to show only those clients that belong to the respective user.

...the code behind: 

String strConnString = ConfigurationManager
    .ConnectionStrings["BA_2013ConnectionString"].ConnectionString;
SqlConnection con = new SqlConnection(strConnString);
SqlCommand cmd = new SqlCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "getClients";
cmd.Parameters
    .Add("@UserId", SqlDbType.UniqueIdentifier)
    .Value = txtUserId.Text.ToString();
cmd.Connection = con;

con.Open();

gvClients.DataSource = cmd.ExecuteReader();
gvClients.DataBind();

con.Close();
con.Dispose();

...the stored procedure:

ALTER PROCEDURE dbo.getClients
@UserId uniqueidentifier
AS
BEGIN
    SELECT ClientId, UserId, ClientName, EmailAddress, PhoneNumber, ServicesNum 
    FROM  Client_tb 
    WHERE UserId = @UserId  

END

when I run the page, I get the error: Invalid cast from 'System.String' to 'System.Guid ...could I get some help with this please?

Upvotes: 1

Views: 18099

Answers (1)

Habib
Habib

Reputation: 223267

You need to parse the string guid to Guid like:

cmd.Parameters.Add("@UserId", SqlDbType.UniqueIdentifier).Value = Guid.Parse(txtUserId.Text);

You can also pass the string value in a Guid constructor like:

cmd.Parameters.Add("@UserId", SqlDbType.UniqueIdentifier).Value = new Guid(txtUserId.Text);

Also there is no need to call ToString on TextBox's Text Field, it is already of type string.

(Remember Guid.Parse is supported in .Net framework 4.0 and higher)

If you are getting the input from a TextBox then chances are you might encounter invalid values for the Guid in that case you can use Guid.TryParse method.

Upvotes: 5

Related Questions