Conversion error -> character string to uniqueidentifier in asp.net

i have one store procedure like :

ALTER procedure [dbo].[prcDisplayTpTestimonial]
@personname varchar(100),
@orderby varchar(100),
@OrderByDirection varchar(100)

As
Begin
    set nocount on;

select t.id_testimonials,
       (select client_name
        from   tp_Client_Master c
        where  c.client_id = t.client_id) as client_name,
       t.Person_Name,
       t.Description
from   tp_Testimonial_master t
where  t.Person_name like '%' + @personname + '%'
       and t.syncoperation <> 'D'
order  by case
            when @orderby = 'Person_Name'
                 and @OrderByDirection = 'asc' then Person_Name
          end asc,
          case
            when @orderby = 'Person_Name'
                 and @OrderByDirection = 'desc' then Person_Name
          end desc,
          case
            when @orderby = 'Description'
                 and @OrderByDirection = 'asc' then Description
          end asc,
          case
            when @orderby = 'Description'
                 and @OrderByDirection = 'desc' then Description
          end desc  


End

which is work fine but when i run my cs page it give uniqueidentifier error here is my cs code :

SqlCommand cmd1 = new SqlCommand("prcDisplayTpTestim开发者_StackOverflow社区onial", con);
        cmd1.CommandType = CommandType.StoredProcedure;

        cmd1.Parameters.Add(new SqlParameter("@personname", SqlDbType.VarChar)).Value = clientSearch.Text.ToString().Trim();

        cmd1.Parameters.Add(new SqlParameter("@orderby", SqlDbType.VarChar)).Value = sort;
        cmd1.Parameters.Add(new SqlParameter("@OrderByDirection", SqlDbType.VarChar)).Value = sort_direction;


        DataTable dt = new DataTable();
        SqlDataAdapter adp = new SqlDataAdapter(cmd1);
        adp.Fill(dt);
        dgTestimonial.DataSource = dt;
        dgTestimonial.DataBind();

Somewhere, you're passing a string value to a uniqueidentifier field in your database.

Make sure c.client_id and t.client_id are both the same data type.

As far as the data type you choose goes, remember that the uniqueidentifier type is meant more for things like email addresses in a table so that each row has a unique email address on it (for example) - unless I'm mistaken.

For row ID columns, I use either int data types with identity(1,1) on the column, or I use a varchar data type with a default value of new guid().

Hope this helps.