Export (0) Print
Expand All

ObjectDataSource Source Object Example

Illustrates a custom middle-tier business object that can be used with an ObjectDataSource control.

Description

The following code example illustrates a custom middle-tier business object that can be used with an ObjectDataSource control. This topic also illustrates an example ASP.NET page that uses the business object as the source for an ObjectDataSource control. The page includes a GridView control and a DetailsView control that are bound to the ObjectDataSource control.

To use the code, you can create a code file in your Web application's App_Code subdirectory and copy the code into the file. The business object will then be compiled dynamically and included as part of your Web application. Alternatively, you can compile the business object and place it in the Bin directory of an ASP.NET application or in the Global Assembly Cache (GAC). For more information on the App_Code and Bin directories, see Shared Code Folders in ASP.NET Web Site Projects.

Code


using System;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Collections.Generic;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Samples.AspNet.ObjectDataSource
{
  //
  //  Northwind Employee Data Factory
  //

  public class NorthwindData
  {

    private string _connectionString;


    public NorthwindData()
    {
      Initialize();
    }


    public void Initialize()
    {
      // Initialize data source. Use "Northwind" connection string from configuration.

      if (ConfigurationManager.ConnectionStrings["Northwind"] == null ||
          ConfigurationManager.ConnectionStrings["Northwind"].ConnectionString.Trim() == "")
      {
        throw new Exception("A connection string named 'Northwind' with a valid connection string " + 
                            "must exist in the <connectionStrings> configuration section for the application.");
      }

      _connectionString = 
        ConfigurationManager.ConnectionStrings["Northwind"].ConnectionString;
    }


    // Select all employees.

    public DataTable GetAllEmployees(string sortColumns, int startRecord, int maxRecords)
    {
      VerifySortColumns(sortColumns);

      string sqlCmd = "SELECT EmployeeID, LastName, FirstName, Address, City, Region, PostalCode FROM Employees ";

      if (sortColumns.Trim() == "")
        sqlCmd += "ORDER BY EmployeeID";
      else
        sqlCmd += "ORDER BY " + sortColumns;

      SqlConnection  conn = new SqlConnection(_connectionString);
      SqlDataAdapter da   = new SqlDataAdapter(sqlCmd, conn);

      DataSet ds = new DataSet();

      try
      {
        conn.Open();

        da.Fill(ds, startRecord, maxRecords, "Employees");        
      }
      catch (SqlException e)
      {
        // Handle exception.
      }
      finally
      {
        conn.Close();
      }

      return ds.Tables["Employees"];
    }


    public int SelectCount()
    {
      SqlConnection conn = new SqlConnection(_connectionString);
      SqlCommand    cmd  = new SqlCommand("SELECT COUNT(*) FROM Employees", conn); 

      int result = 0;

      try
      {
        conn.Open();

        result = (int)cmd.ExecuteScalar();
      }
      catch (SqlException e)
      {
        // Handle exception.
      }
      finally
      {
        conn.Close();
      }

      return result;
    }


    //////////
    // Verify that only valid columns are specified in the sort expression to avoid a SQL Injection attack.

    private void VerifySortColumns(string sortColumns)
    {
      if (sortColumns.ToLowerInvariant().EndsWith(" desc"))
        sortColumns = sortColumns.Substring(0, sortColumns.Length - 5);

      string[] columnNames = sortColumns.Split(',');

      foreach (string columnName in columnNames)
      {
        switch (columnName.Trim().ToLowerInvariant())
        {
          case "employeeid":
            break;
          case "lastname":
            break;
          case "firstname":
            break;
          case "":
            break;
          default:
            throw new ArgumentException("SortColumns contains an invalid column name.");
            break;
        }
      }
    }



    // Select an employee.

    public DataTable GetEmployee(int EmployeeID)
    {
      SqlConnection  conn = new SqlConnection(_connectionString);
      SqlDataAdapter da   = 
        new SqlDataAdapter("SELECT EmployeeID, LastName, FirstName, Address, City, Region, PostalCode " +
                           "  FROM Employees WHERE EmployeeID = @EmployeeID", conn); 
      da.SelectCommand.Parameters.Add("@EmployeeID", SqlDbType.Int).Value = EmployeeID;

      DataSet ds = new DataSet();

      try
      {
        conn.Open();

        da.Fill(ds, "Employees");
      }
      catch (SqlException e)
      {
        // Handle exception.
      }
      finally
      {
        conn.Close();
      }

      return ds.Tables["Employees"];
    }



    // Delete the Employee by ID.

    public int DeleteEmployee(int EmployeeID)
    {
      SqlConnection conn = new SqlConnection(_connectionString);
      SqlCommand    cmd  = new SqlCommand("DELETE FROM Employees WHERE EmployeeID = @EmployeeID", conn);  
      cmd.Parameters.Add("@EmployeeID", SqlDbType.Int).Value = EmployeeID;

      int result = 0;

      try
      {
        conn.Open();

        result = cmd.ExecuteNonQuery();
      }
      catch (SqlException e)
      {
        // Handle exception.
      }
      finally
      {
        conn.Close();
      }

      return result;
    }


    // Update the Employee by original ID.

    public int UpdateEmployee(int EmployeeID, string LastName, string FirstName,
                              string Address, string City, string Region, string PostalCode)
    {
      if (String.IsNullOrEmpty(FirstName))
        throw new ArgumentException("FirstName cannot be null or an empty string.");
      if (String.IsNullOrEmpty(LastName))
        throw new ArgumentException("LastName cannot be null or an empty string.");

      if (Address    == null) { Address    = String.Empty; }
      if (City       == null) { City       = String.Empty; }
      if (Region     == null) { Region     = String.Empty; }
      if (PostalCode == null) { PostalCode = String.Empty; }

      SqlConnection conn = new SqlConnection(_connectionString);
      SqlCommand    cmd  = new SqlCommand("UPDATE Employees " + 
                                          "  SET FirstName=@FirstName, LastName=@LastName, " + 
                                          "  Address=@Address, City=@City, Region=@Region, " +
                                          "  PostalCode=@PostalCode " +
                                          "  WHERE EmployeeID=@EmployeeID", conn);  

      cmd.Parameters.Add("@FirstName",  SqlDbType.VarChar, 10).Value = FirstName;
      cmd.Parameters.Add("@LastName",   SqlDbType.VarChar, 20).Value = LastName;
      cmd.Parameters.Add("@Address",    SqlDbType.VarChar, 60).Value = Address;
      cmd.Parameters.Add("@City",       SqlDbType.VarChar, 15).Value = City;
      cmd.Parameters.Add("@Region",     SqlDbType.VarChar, 15).Value = Region;
      cmd.Parameters.Add("@PostalCode", SqlDbType.VarChar, 10).Value = PostalCode;
      cmd.Parameters.Add("@EmployeeID", SqlDbType.Int).Value = EmployeeID;

      int result = 0;

      try
      {
        conn.Open();

        result = cmd.ExecuteNonQuery();
      }
      catch (SqlException e)
      {
        // Handle exception.
      }
      finally
      {
        conn.Close();
      }

      return result;
    }


    // Insert an Employee.

    public int InsertEmployee(string LastName, string FirstName,
                               string Address, string City, string Region, string PostalCode)
    {
      if (String.IsNullOrEmpty(FirstName))
        throw new ArgumentException("FirstName cannot be null or an empty string.");
      if (String.IsNullOrEmpty(LastName))
        throw new ArgumentException("LastName cannot be null or an empty string.");

      if (Address    == null) { Address    = String.Empty; }
      if (City       == null) { City       = String.Empty; }
      if (Region     == null) { Region     = String.Empty; }
      if (PostalCode == null) { PostalCode = String.Empty; }

      SqlConnection conn = new SqlConnection(_connectionString);
      SqlCommand    cmd  = new SqlCommand("INSERT INTO Employees " + 
                                          "  (FirstName, LastName, Address, City, Region, PostalCode) " +
                                          "  Values(@FirstName, @LastName, @Address, @City, @Region, @PostalCode); " +
                                          "SELECT @EmployeeID = SCOPE_IDENTITY()", conn);  

      cmd.Parameters.Add("@FirstName",  SqlDbType.VarChar, 10).Value = FirstName;
      cmd.Parameters.Add("@LastName",   SqlDbType.VarChar, 20).Value = LastName;
      cmd.Parameters.Add("@Address",    SqlDbType.VarChar, 60).Value = Address;
      cmd.Parameters.Add("@City",       SqlDbType.VarChar, 15).Value = City;
      cmd.Parameters.Add("@Region",     SqlDbType.VarChar, 15).Value = Region;
      cmd.Parameters.Add("@PostalCode", SqlDbType.VarChar, 10).Value = PostalCode;
      SqlParameter p = cmd.Parameters.Add("@EmployeeID", SqlDbType.Int);
      p.Direction = ParameterDirection.Output;

      int newEmployeeID = 0;

      try
      {
        conn.Open();

        cmd.ExecuteNonQuery();

        newEmployeeID = (int)p.Value;
      }
      catch (SqlException e)
      {
        // Handle exception.
      }
      finally
      {
        conn.Close();
      }

      return newEmployeeID;
    }



    //
    // Methods that support Optimistic Concurrency checks.
    //

    // Delete the Employee by ID.

    public int DeleteEmployee(int original_EmployeeID, string original_LastName, 
                              string original_FirstName, string original_Address,
                              string original_City, string original_Region,
                              string original_PostalCode)
    {
      if (String.IsNullOrEmpty(original_FirstName))
        throw new ArgumentException("FirstName cannot be null or an empty string.");
      if (String.IsNullOrEmpty(original_LastName))
        throw new ArgumentException("LastName cannot be null or an empty string.");

      if (original_Address    == null) { original_Address    = String.Empty; }
      if (original_City       == null) { original_City       = String.Empty; }
      if (original_Region     == null) { original_Region     = String.Empty; }
      if (original_PostalCode == null) { original_PostalCode = String.Empty; }

      string sqlCmd = "DELETE FROM Employees WHERE EmployeeID = @original_EmployeeID " + 
                      " AND LastName = @original_LastName AND FirstName = @original_FirstName " +
                      " AND Address = @original_Address AND City = @original_City " +
                      " AND Region = @original_Region AND PostalCode = @original_PostalCode";

      SqlConnection conn = new SqlConnection(_connectionString);
      SqlCommand cmd = new SqlCommand(sqlCmd, conn); 

      cmd.Parameters.Add("@original_EmployeeID", SqlDbType.Int).Value = original_EmployeeID;
      cmd.Parameters.Add("@original_FirstName",  SqlDbType.VarChar, 10).Value = original_FirstName;
      cmd.Parameters.Add("@original_LastName",   SqlDbType.VarChar, 20).Value = original_LastName;
      cmd.Parameters.Add("@original_Address",    SqlDbType.VarChar, 60).Value = original_Address;
      cmd.Parameters.Add("@original_City",       SqlDbType.VarChar, 15).Value = original_City;
      cmd.Parameters.Add("@original_Region",     SqlDbType.VarChar, 15).Value = original_Region;
      cmd.Parameters.Add("@original_PostalCode", SqlDbType.VarChar, 10).Value = original_PostalCode;

      int result = 0;

      try
      {
        conn.Open();

        result = cmd.ExecuteNonQuery();
      }
      catch (SqlException e)
      {
        // Handle exception.
      }
      finally
      {
        conn.Close();
      }

      return result;
    }


    // Update the Employee by original ID.

    public int UpdateEmployee(int EmployeeID, string LastName, string FirstName,
                              string Address, string City, string Region, string PostalCode,
                              int original_EmployeeID, string original_LastName,
                              string original_FirstName, string original_Address, 
                              string original_City, string original_Region,
                              string original_PostalCode)
    {
      if (String.IsNullOrEmpty(FirstName))
        throw new ArgumentException("FirstName cannot be null or an empty string.");
      if (String.IsNullOrEmpty(LastName))
        throw new ArgumentException("LastName cannot be null or an empty string.");

      if (Address    == null) { Address    = String.Empty; }
      if (City       == null) { City       = String.Empty; }
      if (Region     == null) { Region     = String.Empty; }
      if (PostalCode == null) { PostalCode = String.Empty; }

      if (original_Address    == null) { original_Address    = String.Empty; }
      if (original_City       == null) { original_City       = String.Empty; }
      if (original_Region     == null) { original_Region     = String.Empty; }
      if (original_PostalCode == null) { original_PostalCode = String.Empty; }

      string sqlCmd = "UPDATE Employees " + 
                      "  SET FirstName = @FirstName, LastName = @LastName, " + 
                      "  Address = @Address, City = @City, Region = @Region, " +
                      "  PostalCode = @PostalCode " +
                      "  WHERE EmployeeID = @original_EmployeeID " +
                      " AND LastName = @original_LastName AND FirstName = @original_FirstName " +
                      " AND Address = @original_Address AND City = @original_City " +
                      " AND Region = @original_Region AND PostalCode = @original_PostalCode";

      SqlConnection conn = new SqlConnection(_connectionString);
      SqlCommand cmd = new SqlCommand(sqlCmd, conn); 

      cmd.Parameters.Add("@FirstName",  SqlDbType.VarChar, 10).Value = FirstName;
      cmd.Parameters.Add("@LastName",   SqlDbType.VarChar, 20).Value = LastName;
      cmd.Parameters.Add("@Address",    SqlDbType.VarChar, 60).Value = Address;
      cmd.Parameters.Add("@City",       SqlDbType.VarChar, 15).Value = City;
      cmd.Parameters.Add("@Region",     SqlDbType.VarChar, 15).Value = Region;
      cmd.Parameters.Add("@PostalCode", SqlDbType.VarChar, 10).Value = PostalCode;
      cmd.Parameters.Add("@original_EmployeeID", SqlDbType.Int).Value = original_EmployeeID;
      cmd.Parameters.Add("@original_FirstName",  SqlDbType.VarChar, 10).Value = original_FirstName;
      cmd.Parameters.Add("@original_LastName",   SqlDbType.VarChar, 20).Value = original_LastName;
      cmd.Parameters.Add("@original_Address",    SqlDbType.VarChar, 60).Value = original_Address;
      cmd.Parameters.Add("@original_City",       SqlDbType.VarChar, 15).Value = original_City;
      cmd.Parameters.Add("@original_Region",     SqlDbType.VarChar, 15).Value = original_Region;
      cmd.Parameters.Add("@original_PostalCode", SqlDbType.VarChar, 10).Value = original_PostalCode;

      int result = 0;

      try
      {
        conn.Open();

        result = cmd.ExecuteNonQuery();
      }
      catch (SqlException e)
      {
        // Handle exception.
      }
      finally
      {
        conn.Close();
      }

      return result;
    }

  }
}



<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

  void EmployeesDetailsView_ItemInserted(Object sender, DetailsViewInsertedEventArgs e)
  {
    EmployeesGridView.DataBind();  
  }


  void EmployeesDetailsView_ItemUpdated(Object sender, DetailsViewUpdatedEventArgs e)
  {
    EmployeesGridView.DataBind();
  }


  void EmployeesDetailsView_ItemDeleted(Object sender, DetailsViewDeletedEventArgs e)
  {
    EmployeesGridView.DataBind();
  }

  void EmployeesGridView_OnSelectedIndexChanged(object sender, EventArgs e)
  {
    EmployeeDetailsObjectDataSource.SelectParameters["EmployeeID"].DefaultValue = 
      EmployeesGridView.SelectedDataKey.Value.ToString();
    EmployeesDetailsView.DataBind();
  }

  void EmployeeDetailsObjectDataSource_OnInserted(object sender, ObjectDataSourceStatusEventArgs e)
  {
    EmployeeDetailsObjectDataSource.SelectParameters["EmployeeID"].DefaultValue = 
      e.ReturnValue.ToString();
    EmployeesDetailsView.DataBind();
  }

  void EmployeeDetailsObjectDataSource_OnUpdated(object sender, ObjectDataSourceStatusEventArgs e)
  {
    if ((int)e.ReturnValue == 0)
      Msg.Text = "Employee was not updated. Please try again.";
  }

  void EmployeeDetailsObjectDataSource_OnDeleted(object sender, ObjectDataSourceStatusEventArgs e)
  {
    if ((int)e.ReturnValue == 0)
      Msg.Text = "Employee was not deleted. Please try again.";
  }

  void Page_Load()
  {
    Msg.Text = "";
  }

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ObjectDataSource Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>ObjectDataSource Example</h3>
      <asp:Label id="Msg" runat="server" ForeColor="Red" />

      <asp:ObjectDataSource 
        ID="EmployeesObjectDataSource" 
        runat="server" 
        TypeName="Samples.AspNet.ObjectDataSource.NorthwindData" 
        SortParameterName="SortColumns"
        EnablePaging="true"
        SelectCountMethod="SelectCount"
        StartRowIndexParameterName="StartRecord"
        MaximumRowsParameterName="MaxRecords" 
        SelectMethod="GetAllEmployees" >
      </asp:ObjectDataSource>


      <asp:ObjectDataSource 
        ID="EmployeeDetailsObjectDataSource" 
        runat="server" 
        TypeName="Samples.AspNet.ObjectDataSource.NorthwindData" 
        ConflictDetection="CompareAllValues"
        OldValuesParameterFormatString="original_{0}"
        SelectMethod="GetEmployee"
        InsertMethod="InsertEmployee"
        UpdateMethod="UpdateEmployee"
        DeleteMethod="DeleteEmployee"
        OnInserted="EmployeeDetailsObjectDataSource_OnInserted"
        OnUpdated="EmployeeDetailsObjectDataSource_OnUpdated"
        OnDeleted="EmployeeDetailsObjectDataSource_OnDeleted">
        <SelectParameters>
          <asp:Parameter Name="EmployeeID" Type="Int32" />  
        </SelectParameters>
      </asp:ObjectDataSource>


      <table cellspacing="10">
        <tr>
          <td valign="top">
            <asp:GridView ID="EmployeesGridView" 
              DataSourceID="EmployeesObjectDataSource" 
              AutoGenerateColumns="false"
              AllowSorting="true"
              AllowPaging="true"
              PageSize="5"
              DataKeyNames="EmployeeID" 
              OnSelectedIndexChanged="EmployeesGridView_OnSelectedIndexChanged"
              RunAt="server">

              <HeaderStyle backcolor="lightblue" forecolor="black"/>

              <Columns>                
                <asp:ButtonField Text="Details..."
                                 HeaderText="Show Details"
                                 CommandName="Select"/>  

                <asp:BoundField DataField="EmployeeID" HeaderText="Employee ID" SortExpression="EmployeeID" />
                <asp:BoundField DataField="FirstName"  HeaderText="First Name" SortExpression="FirstName" />
                <asp:BoundField DataField="LastName"   HeaderText="Last Name" SortExpression="LastName, FirstName" />                    
              </Columns>                
            </asp:GridView>            
          </td>
          <td valign="top">                
            <asp:DetailsView ID="EmployeesDetailsView"
              DataSourceID="EmployeeDetailsObjectDataSource"
              AutoGenerateRows="false"
              EmptyDataText="No records."      
              DataKeyNames="EmployeeID"     
              Gridlines="Both" 
              AutoGenerateInsertButton="true"
              AutoGenerateEditButton="true"
              AutoGenerateDeleteButton="true"
              OnItemInserted="EmployeesDetailsView_ItemInserted"
              OnItemUpdated="EmployeesDetailsView_ItemUpdated"
              OnItemDeleted="EmployeesDetailsView_ItemDeleted" 
              RunAt="server">

              <HeaderStyle backcolor="Navy" forecolor="White"/>

              <RowStyle backcolor="White"/>

              <AlternatingRowStyle backcolor="LightGray"/>

              <EditRowStyle backcolor="LightCyan"/>

              <Fields>                  
                <asp:BoundField DataField="EmployeeID" HeaderText="Employee ID" InsertVisible="False" ReadOnly="true"/>                    
                <asp:BoundField DataField="FirstName"  HeaderText="First Name"/>
                <asp:BoundField DataField="LastName"   HeaderText="Last Name"/>                    
                <asp:BoundField DataField="Address"    HeaderText="Address"/>                    
                <asp:BoundField DataField="City"       HeaderText="City"/>                        
                <asp:BoundField DataField="Region"     HeaderText="Region"/>
                <asp:BoundField DataField="PostalCode" HeaderText="Postal Code"/>                    
              </Fields>                    
            </asp:DetailsView>
          </td>                
        </tr>            
      </table>
    </form>
  </body>
</html>


Comments

The example requires a connection string for the sample Northwind database on a SQL Server. The connection string must be defined in the <connectionStrings> element of the application's configuration file. The connectionStrings section might look like the following example:

<configuration>
  <system.web>
    <connectionStrings>
      <add 
        name="Northwind" 
        connectionString="Data Source=localhost;Integrated Security=SSPI;Initial Catalog=Northwind;" />
    </connectionStrings>
  </system.web>
</configuration>

Community Additions

ADD
Show:
© 2014 Microsoft