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ptg 784 public void UpdateMovie(int id, string title, string director, DateTime ➥ dateReleased) { // Create Command SqlConnection con = new SqlConnection(_conString); SqlCommand cmd = new SqlCommand(); cmd.Connection = con; cmd.CommandText = “UPDATE Movies SET Title=@Title,Director=@Director,DateReleased= // Add parameters cmd.Parameters.AddWithValue(“@Title”, title); cmd.Parameters.AddWithValue(“@Director”, director); cmd.Parameters.AddWithValue(“@DateReleased”, dateReleased); cmd.Parameters.AddWithValue(“@Id”, id); // Execute command using (con) { con.Open(); cmd.ExecuteNonQuery(); } } public SqlDataReader GetMovies() { // Create Connection SqlConnection con = new SqlConnection(_conString); // Create Command SqlCommand cmd = new SqlCommand(); cmd.Connection = con; cmd.CommandText = “SELECT Id,Title,Director,DateReleased FROM Movies”; // Return DataReader con.Open(); return cmd.ExecuteReader(CommandBehavior.CloseConnection); } public Movies() { _conString = WebConfigurationManager.ConnectionStrings[“Movies”].ConnectionString; } } CHAPTER 18 Using the ObjectDataSource Control From the Library of Wow! eBook ptg 785 Using Parameters with the ObjectDataSource Control 18 The page in Listing 18.12 contains a GridView and ObjectDataSource control. The ObjectDataSource control includes an UpdateMethod property that points to the UpdateMovie() method. LISTING 18.12 ShowMovies.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”> <html xmlns=”http://www.w3.org/1999/xhtml” > <head id=”Head1” runat=”server”> <title>Show Movies</title> </head> <body> <form id=”form1” runat=”server”> <div> <asp:GridView id=”grdMovies” DataSourceID=”srcMovies” DataKeyNames=”Id” AutoGenerateEditButton=”true” Runat=”server” /> <asp:ObjectDataSource id=”srcMovies” TypeName=”Movies” SelectMethod=”GetMovies” UpdateMethod=”UpdateMovie” Runat=”server”/> </div> </form> </body> </html> In Listing 18.12, the GridView automatically adds the update parameters to the ObjectDataSource control’s UpdateParameters collection. As an alternative, you can declare the parameters used by the ObjectDataSource control explicitly. For example, the page in Listing 18.13 declares all the parameters passed to the UpdateMovie() method. LISTING 18.13 ExplicitShowMovies.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”> From the Library of Wow! eBook ptg 786 <html xmlns=”http://www.w3.org/1999/xhtml” > <head id=”Head1” runat=”server”> <title>Show Movies</title> </head> <body> <form id=”form1” runat=”server”> <div> <asp:GridView id=”grdMovies” DataSourceID=”srcMovies” DataKeyNames=”Id” AutoGenerateEditButton=”true” Runat=”server” /> <asp:ObjectDataSource id=”srcMovies” TypeName=”Movies” SelectMethod=”GetMovies” UpdateMethod=”UpdateMovie” Runat=”server”> <UpdateParameters> <asp:Parameter Name=”title” /> <asp:Parameter Name=”director” /> <asp:Parameter Name=”dateReleased” Type=”DateTime” /> <asp:Parameter Name=”id” Type=”Int32” /> </UpdateParameters> </asp:ObjectDataSource> </div> </form> </body> </html> The ObjectDataSource uses reflection to match its parameters against the parameters of the method that it calls. The order of the parameters does not matter, and the case of the parameters does not matter. However, the one thing that does matter is the names of the parameters. You specify the type of a parameter with the Type property, which represents a member of the TypeCode enumeration. The TypeCode enumeration represents an enumeration of common .NET Framework data types such as Int32, Decimal, and DateTime. If the enumeration does not include a data type that you need, you can use the TypeCode.Object member from the enumeration. CHAPTER 18 Using the ObjectDataSource Control From the Library of Wow! eBook ptg 787 Using Parameters with the ObjectDataSource Control 18 Using Different Parameter Types You can use all the same types of parameters with the ObjectDataSource control that you can use with the SqlDataSource control: . Parameter—Represents an arbitrary static value. . ControlParameter—Represents the value of a control or page property. . CookieParameter—Represents the value of a browser cookie. . FormParameter—Represents the value of an HTML form field. . ProfileParameter—Represents the value of a Profile property. . QueryStringParameter—Represents the value of a query string field. . SessionParameter—Represents the value of an item stored in Session state. For example, the page in Listing 18.14 contains a DropDownList control and a GridView control, which enables you to view movies that match a selected category (see Figure 18.3). FIGURE 18.3 Displaying movies by category. LISTING 18.14 ShowMoviesByCategory.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”> <html xmlns=”http://www.w3.org/1999/xhtml” > From the Library of Wow! eBook ptg 788 <head id=”Head1” runat=”server”> <style type=”text/css”> .movies { border:Solid 1px black; } .movies td,.movies th { padding:5px; } </style> <title>Show Movies by Category</title> </head> <body> <form id=”form1” runat=”server”> <div> <asp:DropDownList id=”ddlMovieCategory” DataSourceID=”srcMovieCategories” DataTextField=”Name” DataValueField=”Id” ToolTip=”Movie Category” Runat=”server” /> <asp:Button id=”btnSelect” Text=”Select” Runat=”server” /> <asp:GridView id=”grdMovies” DataSourceID=”srcMovies” CssClass=”movies” GridLines=”None” Runat=”server” /> <asp:ObjectDataSource id=”srcMovieCategories” TypeName=”MovieCategories” SelectMethod=”GetCategories” Runat=”server” /> <asp:ObjectDataSource id=”srcMovies” TypeName=”MovieCategories” SelectMethod=”GetMovies” CHAPTER 18 Using the ObjectDataSource Control From the Library of Wow! eBook ptg 789 Using Parameters with the ObjectDataSource Control 18 Runat=”server”> <SelectParameters> <asp:ControlParameter Name=”CategoryId” ControlID=”ddlMovieCategory” /> </SelectParameters> </asp:ObjectDataSource> </div> </form> </body> </html> The ObjectDataSource control in Listing 18.14 is bound to the component contained in Listing 18.15. The ObjectDataSource control includes a SelectParameters collection. The SelectParameters collection contains a ControlParameter, which represents the current value of the ddlMovieCategory DropDownList control. LISTING 18.15 MovieCategories.cs using System; using System.Data; using System.Data.SqlClient; using System.Web.Configuration; public class MovieCategories { private readonly string _conString; public SqlDataReader GetMovies(int categoryId) { // Create Connection SqlConnection con = new SqlConnection(_conString); // Create Command SqlCommand cmd = new SqlCommand(); cmd.Connection = con; cmd.CommandText = “SELECT Id,Title,Director,DateReleased “ + “ FROM Movies WHERE CategoryId=@CategoryId”; // Add parameters cmd.Parameters.AddWithValue(“@CategoryId”, categoryId); // Return DataReader con.Open(); From the Library of Wow! eBook ptg 790 CHAPTER 18 Using the ObjectDataSource Control return cmd.ExecuteReader(CommandBehavior.CloseConnection); } public SqlDataReader GetCategories() { // Create Connection SqlConnection con = new SqlConnection(_conString); // Create Command SqlCommand cmd = new SqlCommand(); cmd.Connection = con; cmd.CommandText = “SELECT Id,Name FROM MovieCategories”; // Return DataReader con.Open(); return cmd.ExecuteReader(CommandBehavior.CloseConnection); } public MovieCategories() { _conString = WebConfigurationManager.ConnectionStrings[“Movies”].ConnectionString; } } Passing Objects as Parameters Passing long lists of parameters to methods can make it difficult to maintain an applica- tion. If the list of parameters changes, you need to update every method that accepts the list of parameters. Rather than pass a list of parameters to a method, you can pass a partic- ular object. For example, you can pass a CompanyEmployee object to a method used to update an employee, rather than a list of parameters that represent employee properties. If you specify a value for an ObjectDataSource control’s DataObjectTypeName property, you can pass an object rather than a list of parameters to the methods that an ObjectDataSource represents. In that case, the ObjectDataSource parameters represent properties of the object. For example, the EmployeeData component in Listing 18.16 contains an InsertEmployee() method for creating a new employee. This method is passed an instance of the CompanyEmployee object that represents a particular employee. The CompanyEmployee class also is included in Listing 18.16. From the Library of Wow! eBook ptg 791 Using Parameters with the ObjectDataSource Control 18 LISTING 18.16 EmployeeData.cs using System; using System.Data; using System.Data.SqlClient; using System.Collections.Generic; using System.Web.Configuration; public class EmployeeData { string _connectionString; public void UpdateEmployee(CompanyEmployee employeeToUpdate) { // Initialize ADO.NET objects SqlConnection con = new SqlConnection(_connectionString); SqlCommand cmd = new SqlCommand(); cmd.CommandText = “UPDATE Employees SET FirstName=@FirstName,” + “LastName=@LastName,Phone=@Phone WHERE Id=@Id”; cmd.Connection = con; // Create parameters cmd.Parameters.AddWithValue(“@Id”, employeeToUpdate.Id); cmd.Parameters.AddWithValue(“@FirstName”, employeeToUpdate.FirstName); cmd.Parameters.AddWithValue(“@LastName”, employeeToUpdate.LastName); cmd.Parameters.AddWithValue(“@Phone”, employeeToUpdate.Phone); // Execute command using (con) { con.Open(); cmd.ExecuteNonQuery(); } } public List<CompanyEmployee> GetEmployees() { List<CompanyEmployee> employees = new List<CompanyEmployee>(); SqlConnection con = new SqlConnection(_connectionString); SqlCommand cmd = new SqlCommand(); cmd.CommandText = “SELECT Id,FirstName,LastName,Phone FROM Employees”; cmd.Connection = con; using (con) { con.Open(); From the Library of Wow! eBook ptg 792 CHAPTER 18 Using the ObjectDataSource Control SqlDataReader reader = cmd.ExecuteReader(); while (reader.Read()) { CompanyEmployee newEmployee = new CompanyEmployee(); newEmployee.Id = (int)reader[“Id”]; newEmployee.FirstName = (string)reader[“FirstName”]; newEmployee.LastName = (string)reader[“LastName”]; newEmployee.Phone = (string)reader[“Phone”]; employees.Add(newEmployee); } } return employees; } public EmployeeData() { _connectionString = WebConfigurationManager.ConnectionStrings[“Employees”].ConnectionString; } } public class CompanyEmployee { private int _id; private string _firstName; private string _lastName; private string _phone; public int Id { get { return _id; } set { _id = value; } } public string FirstName { get { return _firstName; } set { _firstName = value; } } public string LastName { get { return _lastName; } set { _lastName = value; } } From the Library of Wow! eBook ptg 793 Using Parameters with the ObjectDataSource Control 18 public string Phone { get { return _phone; } set { _phone = value; } } } The page in Listing 18.17 contains a DetailsView control and an ObjectDataSource control. The DetailsView control enables you to update existing employees in the Employees database table. LISTING 18.17 UpdateEmployees.aspx <%@ Page Language=”C#” %> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”> <html xmlns=”http://www.w3.org/1999/xhtml” > <head id=”Head1” runat=”server”> <title>Update Employees</title> </head> <body> <form id=”form1” runat=”server”> <div> <asp:DetailsView ID=”DetailsView1” DataSourceID=”srcEmployees” DataKeyNames=”Id” AutoGenerateRows=”True” AutoGenerateEditButton=”True” AllowPaging=”true” Runat=”server” /> <asp:ObjectDataSource id=”srcEmployees” TypeName=”EmployeeData” DataObjectTypeName=”CompanyEmployee” SelectMethod=”GetEmployees” UpdateMethod=”UpdateEmployee” Runat=”server” /> </div> </form> </body> </html> From the Library of Wow! eBook . id=”srcMovies” TypeName=”Movies” SelectMethod=”GetMovies” UpdateMethod=”UpdateMovie” Runat=”server”> <UpdateParameters> < ;asp: Parameter Name=”title” /> < ;asp: Parameter Name=”director” /> < ;asp: Parameter Name=”dateReleased”. or page property. . CookieParameter—Represents the value of a browser cookie. . FormParameter—Represents the value of an HTML form field. . ProfileParameter—Represents the value of a Profile property. list of parameters. Rather than pass a list of parameters to a method, you can pass a partic- ular object. For example, you can pass a CompanyEmployee object to a method used to update an employee,
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