Delete a row from a SQL Server table

Question

I'm trying to simply delete a full row from my SQL Server database table using a button event. So far none of my attempts have succeeded. This is what I'm trying to do:

public static void deleteRow(string table, string columnName, string IDNumber)
{
    try
    {
    using (SqlConnection con = new SqlConnection(Global.connectionString))
    {
         con.Open();
         using (SqlCommand command = new SqlCommand("DELETE FROM " + table + " WHERE " + columnName + " = " + IDNumber, con))
         {
               command.ExecuteNonQuery();
         }
         con.Close();
    }
    }
    catch (SystemException ex)
       {
       MessageBox.Show(string.Format("An error occurred: {0}", ex.Message));
       }
    }
}

I keep receiving the error:

A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll An error occurred: Operand type clash: text is incompatible with int

All of the columns in the table are of TEXT type. Why cannot I compare the function argument of type string to the columns to find the match? (And then delete the row?)