Sdílet prostřednictvím


ObjectDataSource.DeleteParameters Vlastnost

Definice

Získá kolekci parametrů, která obsahuje parametry, které jsou používány metodou DeleteMethod .

public:
 property System::Web::UI::WebControls::ParameterCollection ^ DeleteParameters { System::Web::UI::WebControls::ParameterCollection ^ get(); };
[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
public System.Web.UI.WebControls.ParameterCollection DeleteParameters { get; }
[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
member this.DeleteParameters : System.Web.UI.WebControls.ParameterCollection
Public ReadOnly Property DeleteParameters As ParameterCollection

Hodnota vlastnosti

A ParameterCollection , který obsahuje parametry používané metodou DeleteMethod .

Atributy

Příklady

Tato část obsahuje dva příklady kódu. První příklad kódu ukazuje, jak použít ObjectDataSource objekt s obchodním objektem a ovládacím GridView prvku k odstranění dat. Druhý příklad kódu ukazuje EmployeeLogic třídu, která se používá v prvním příkladu kódu.

Následující příklad kódu ukazuje, jak použít DeleteParameters vlastnost ObjectDataSource ovládacího prvku s obchodním objektem a ovládacím GridView prvku k odstranění dat. Zpočátku GridView ovládací prvek zobrazí sadu všech zaměstnanců pomocí metody, která je určena SelectMethod vlastností k načtení dat z objektu EmployeeLogic . Vzhledem k tomu, že AutoGenerateDeleteButton vlastnost je nastavená GridView na true, ovládací prvek automaticky zobrazí tlačítko Odstranit.

Pokud kliknete na tlačítko Odstranit , Deleting bude událost volána se dvěma parametry. Jeden parametr , EmpIDpochází z DataGrid ovládacího prvku a je založený na DataKeyNames vlastnosti . Druhý parametr pochází z deklarativní DeleteParameters vlastnosti. Třída EmployeeLogic přetíží metodu DeleteEmployee . Jedno přetížení přebírá NorthwindEmployee parametr a druhé přebírá Int32 parametr s názvem anID. V případě Deleting , že položky ve InputParameters vlastnosti jsou upraveny tak, aby obsahovaly pouze jeden parametr s názvem anID s hodnotou z original_EmpID. Pokud obslužná rutina události existuje, je volána odpovídající DeleteEmployee metoda.

Následující příklad kódu ukazuje webovou stránku, která zobrazuje DataGrid ovládací prvek a zpracovává Deleting událost.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" Assembly="Samples.AspNet.CS" %>
<%@ Import namespace="Samples.AspNet.CS" %>
<%@ 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">
private void NorthwindEmployeeDeleting(object source, ObjectDataSourceMethodEventArgs e)
{
  IDictionary paramsFromPage = e.InputParameters;

  paramsFromPage.Remove("anID");
  paramsFromPage.Add("anID", (int)paramsFromPage["EmpID"]);
  paramsFromPage.Remove("EmpID");
    
}
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - C# Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <asp:gridview
          id="GridView1"
          runat="server"
          datasourceid="ObjectDataSource1"
          autogeneratedeletebutton="true"
          DataKeyNames="EmpID">
        </asp:gridview>

        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          deletemethod="DeleteEmployee"
          OnDeleting="NorthwindEmployeeDeleting"
          typename="Samples.AspNet.CS.EmployeeLogic">
          <deleteparameters>
            <asp:parameter name="anID" type="Int32" />
          </deleteparameters>
        </asp:objectdatasource>

    </form>
  </body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" Assembly="Samples.AspNet.VB" %>
<%@ Import namespace="Samples.AspNet.VB" %>
<%@ Page language="vb" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Private Sub NorthwindEmployeeDeleting(source As Object, e As ObjectDataSourceMethodEventArgs)

  Dim paramsFromPage As IDictionary = e.InputParameters

  paramsFromPage.Remove("anID")
  paramsFromPage.Add("anID", CInt(paramsFromPage("EmpID")))
  paramsFromPage.Remove("EmpID")

End Sub ' NorthwindEmployeeDeleting
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - VB Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <asp:gridview
          id="GridView1"
          runat="server"
          datasourceid="ObjectDataSource1"
          autogeneratedeletebutton="true"
          DataKeyNames="EmpID">
        </asp:gridview>

        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          deletemethod="DeleteEmployee"
          OnDeleting="NorthwindEmployeeDeleting"
          typename="Samples.AspNet.VB.EmployeeLogic">
          <deleteparameters>
            <asp:parameter name="anID" type="Int32" />
          </deleteparameters>
        </asp:objectdatasource>

    </form>
  </body>
</html>

Následující příklad kódu ukazuje EmployeeLogic třídu, která se používá v předchozím příkladu kódu.

namespace Samples.AspNet.CS {

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI;
using System.Web.UI.WebControls;
  //
  // EmployeeLogic is a stateless business object that encapsulates
  // the operations you can perform on a NorthwindEmployee object.
  //
  public class EmployeeLogic {

    // Returns a collection of NorthwindEmployee objects.
    public static ICollection GetAllEmployees () {
      ArrayList al = new ArrayList();

      // Use the SqlDataSource class to wrap the
      // ADO.NET code required to query the database.
      ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];

      SqlDataSource sds
        = new SqlDataSource(cts.ConnectionString,
                            "SELECT EmployeeID FROM Employees");
      try {
        IEnumerable IDs = sds.Select(DataSourceSelectArguments.Empty);

        // Iterate through the Enumeration and create a
        // NorthwindEmployee object for each ID.
        IEnumerator enumerator = IDs.GetEnumerator();
        while (enumerator.MoveNext()) {
          // The IEnumerable contains DataRowView objects.
          DataRowView row = enumerator.Current as DataRowView;
          int id = (int) row["EmployeeID"];
          NorthwindEmployee nwe = new NorthwindEmployee(id);
          // Add the NorthwindEmployee object to the collection.
          al.Add(nwe);
        }
      }
      finally {
        // If anything strange happens, clean up.
        sds.Dispose();
      }

      return al;
    }

    public static NorthwindEmployee GetEmployee(int anID) {
      return new NorthwindEmployee(anID);
    }

    public static void DeleteEmployee(NorthwindEmployee ne) {
      bool retval = ne.Delete();
      if (! retval) { throw new NorthwindDataException("Employee delete failed."); }
      // Delete the object in memory.
      ne = null;
    }

    public static void DeleteEmployee(int anID) {
        NorthwindEmployee tempEmp = new NorthwindEmployee(anID);
        DeleteEmployee(tempEmp);
    }
  }
  public class NorthwindEmployee {

    public NorthwindEmployee (int anID) {
      this.ID = anID;

      ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
      SqlConnection conn = new SqlConnection (cts.ConnectionString);
      SqlCommand sc =
        new SqlCommand(" SELECT FirstName,LastName " +
                       " FROM Employees " +
                       " WHERE EmployeeID = @empId",
                       conn);
      // Add the employee ID parameter and set its value.
      sc.Parameters.Add(new SqlParameter("@empId",SqlDbType.Int)).Value = Int32.Parse(anID.ToString());
      SqlDataReader sdr = null;

      try {
        conn.Open();
        sdr = sc.ExecuteReader();

        // This is not a while loop. It only loops once.
        if (sdr != null && sdr.Read()) {
          // The IEnumerable contains DataRowView objects.
          this.firstName        = sdr["FirstName"].ToString();
          this.lastName         = sdr["LastName"].ToString();
        }
        else {
          throw new NorthwindDataException("Data not loaded for employee id.");
        }
      }
      finally {
        try {
          if (sdr != null) sdr.Close();
          conn.Close();
        }
        catch (SqlException) {
          // Log an event in the Application Event Log.
          throw;
        }
      }
    }

    private object ID;
    public object EmpID {
      get { return ID; }
    }

    private string lastName;
    public string LastName {
      get { return lastName; }
      set { lastName = value; }
    }

    private string firstName;
    public string FirstName {
      get { return firstName; }
      set { firstName = value;  }
    }
    public bool Delete () {
      if (ID.Equals(DBNull.Value)) {
        // The Employee object is not persisted.
        return true;
      }
      else {
        // The Employee object is persisted.
        // Use the SqlDataSource control as a convenient wrapper for
        // the ADO.NET code needed to delete a record from the database.
        ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
        SqlDataSource sds = new SqlDataSource();
        try {
          sds.ConnectionString = cts.ConnectionString;
          sds.DeleteCommand = "DELETE FROM Employees WHERE EmployeeID=@empID;";
          sds.DeleteParameters.Add(new Parameter("empID",TypeCode.Int32,this.ID.ToString()));

          /* To make this sample fully functional, uncomment these lines
          int retval = sds.Delete();
          if (retval == 1) { return true; }
          return false; */

          return true;
        }
        finally {
          sds.Dispose();
        }
      }
    }
  }
  internal class NorthwindDataException: Exception {
    public NorthwindDataException(string msg) : base (msg) { }
  }
}
Imports System.Collections
Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.UI
Imports System.Web.UI.WebControls

Namespace Samples.AspNet.VB
'
' EmployeeLogic is a stateless business object that encapsulates
' the operations you can perform on a NorthwindEmployee object.
Public Class EmployeeLogic

   ' Returns a collection of NorthwindEmployee objects.
   Public Shared Function GetAllEmployees() As ICollection
      Dim al As New ArrayList()

      ' Use the SqlDataSource class to wrap the
      ' ADO.NET code required to query the database.
      Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection")
      Dim sds As New SqlDataSource(cts.ConnectionString, "SELECT EmployeeID FROM Employees")
      Try
         Dim IDs As IEnumerable = sds.Select(DataSourceSelectArguments.Empty)

         ' Iterate through the Enumeration and create a
         ' NorthwindEmployee object for each ID.
         Dim enumerator As IEnumerator = IDs.GetEnumerator()
         While enumerator.MoveNext()
            ' The IEnumerable contains DataRowView objects.
            Dim row As DataRowView = CType(enumerator.Current,DataRowView)
            Dim id As String = row("EmployeeID").ToString()
                    Dim nwe As New NorthwindEmployee(CInt(id))
            ' Add the NorthwindEmployee object to the collection.
            al.Add(nwe)
         End While
      Finally
         ' If anything strange happens, clean up.
         sds.Dispose()
      End Try

      Return al
   End Function 'GetAllEmployees


   Public Shared Function GetEmployee(anID As Integer) As NorthwindEmployee
      Return New NorthwindEmployee(anID)
   End Function 'GetEmployee


   Public Shared Sub DeleteEmployee(ne As NorthwindEmployee)
      Dim retval As Boolean = ne.Delete()
      If Not retval Then
         Throw New NorthwindDataException("Employee delete failed.")
      End If ' Delete the object in memory.
      ne = Nothing
   End Sub


   Public Shared Sub DeleteEmployee(anID As Integer)
      Dim tempEmp As New NorthwindEmployee(anID)
      DeleteEmployee(tempEmp)
   End Sub

   ' And so on...

End Class

Public Class NorthwindEmployee

   Public Sub New(anID As Integer)
      Me.ID = anID
      Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection")
      Dim conn As New SqlConnection(cts.ConnectionString)
      Dim sc As New SqlCommand(" SELECT FirstName,LastName " & _
                               " FROM Employees " & _
                               " WHERE EmployeeID = @empId", conn)
      ' Add the employee ID parameter and set its value.
      sc.Parameters.Add(New SqlParameter("@empId", SqlDbType.Int)).Value = Int32.Parse(anID.ToString())
      Dim sdr As SqlDataReader = Nothing

      Try
         conn.Open()
         sdr = sc.ExecuteReader()

         ' This is not a while loop. It only loops once.
         If Not (sdr Is Nothing) AndAlso sdr.Read() Then
            ' The IEnumerable contains DataRowView objects.
            Me.firstName = sdr("FirstName").ToString()
            Me.lastName = sdr("LastName").ToString()
         Else
            Throw New NorthwindDataException("Data not loaded for employee id.")
         End If
      Finally
         Try
            If Not (sdr Is Nothing) Then
               sdr.Close()
            End If
            conn.Close()
         Catch se As SqlException
            ' Log an event in the Application Event Log.
            Throw
         End Try
      End Try
   End Sub

   Private ID As Object
   Public ReadOnly Property EmpID() As Object
      Get
         Return ID
      End Get
   End Property

   Private aLastName As String
   Public Property LastName() As String
      Get
         Return aLastName
      End Get
      Set
         aLastName = value
      End Set
   End Property

   Private aFirstName As String
   Public Property FirstName() As String
      Get
         Return aFirstName
      End Get
      Set
         aFirstName = value
      End Set
   End Property

   Public Function Delete() As Boolean
      If ID.Equals(DBNull.Value) Then
         ' The Employee object is not persisted.
         Return True
      Else
         ' The Employee object is persisted.
         ' Use the SqlDataSource control as a convenient wrapper for
         ' the ADO.NET code needed to delete a record from the database.
         Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection")
         Dim sds As New SqlDataSource()
         Try
            sds.ConnectionString = cts.ConnectionString
            sds.DeleteCommand = "DELETE FROM Employees WHERE EmployeeID=@empID;"
                    Dim param As New Parameter("empID", TypeCode.Int32, CStr(Me.ID))
            sds.DeleteParameters.Add(param)

            ' To make this sample fully functional, uncomment these lines
'          int retval = sds.Delete();
'          if (retval == 1) { return true; }
'          return false;

            Return True
         Finally
            sds.Dispose()
         End Try
      End If
   End Function 'Delete

End Class

Friend Class NorthwindDataException
   Inherits Exception

   Public Sub New(msg As String)
      MyBase.New(msg)
   End Sub
End Class

End Namespace

Poznámky

Názvy a typy parametrů obsažených v kolekci DeleteParameters musí odpovídat názvům a typům parametrů v DeleteMethod podpisu metody. Názvy parametrů jsou ovlivněny OldValuesParameterFormatString vlastností a rozlišují se malá a malá písmena. Parametry v kolekci závisí na datech, která jsou v ovládacím prvku vázaném na data, na parametrech, které jsou zadány deklarativně, a na parametrech, které jsou přidány programově. Další informace najdete v tématech "Sloučení parametrů" v Delete a Použití parametrů s ovládacím prvku ObjectDataSource.

Vlastnost DeleteParameters načte DeleteParameters vlastnost, která je obsažena objektem ObjectDataSourceView , který je přidružen k ovládacímu ObjectDataSource prvku.

Další informace o slučování parametrů, životnosti objektu a řešení metody najdete v tématu DeleteMethod.

Platí pro

Viz také