DataControlFieldCollection.Item[Int32] Eigenschap

Definitie

Naamruimte:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Hiermee wordt het DataControlField object opgehaald of ingesteld op de opgegeven index in de verzameling.

public:
 property System::Web::UI::WebControls::DataControlField ^ default[int] { System::Web::UI::WebControls::DataControlField ^ get(int index); };
[System.ComponentModel.Browsable(false)]
public System.Web.UI.WebControls.DataControlField this[int index] { get; }
[<System.ComponentModel.Browsable(false)>]
member this.Item(int) : System.Web.UI.WebControls.DataControlField
Default Public ReadOnly Property Item(index As Integer) As DataControlField

Parameters

index
Int32

De op nul gebaseerde index van de DataControlField index die moet worden opgehaald uit de verzameling.

Waarde van eigenschap

DataControlField

De DataControlField op de opgegeven index in de verzameling.

Kenmerken
BrowsableAttribute

Voorbeelden

In het volgende codevoorbeeld ziet u hoe u de Item[] indexeerfunctie gebruikt om toegang te krijgen tot de velden van een GridView besturingselement wanneer de gebruiker op een knop in het besturingselement klikt.

<%@ Page language="C#" %>

<script runat="server">

  void AuthorsGridView_RowCommand(Object sender, GridViewCommandEventArgs e)
  {
  
    // If multiple ButtonField columns are used, use the
    // CommandName property to determine which button was clicked.
    switch(e.CommandName)
    {
    
      case "Edit":
        AuthorsGridView.Columns[0].Visible = false;
        AuthorsGridView.Columns[1].Visible = true;
        break;
      case "Update":
        AuthorsGridView.Columns[0].Visible = true;
        AuthorsGridView.Columns[1].Visible = false;
        break;
      default:
        // Do nothing.
        break;
    }
    
  }
  
  void AuthorsGridView_RowUpdating (Object sender, GridViewUpdateEventArgs e)
  {
    
    // Retrieve the row being edited.    
    int index = AuthorsGridView.EditIndex;
    GridViewRow row = AuthorsGridView.Rows[index];
    
    // Retrieve the new value for the author's first name from the row. 
    // In this example, the author's first name is in the second cell 
    // of the row (index 1). To get the value, first retrieve the TextBox
    // that contains the value.
    TextBox firstNameTextBox = (TextBox)row.Cells[1].FindControl("FirstNameTextBox");
    
    // Make sure the control was found. 
    String firstName = "";    
    if(firstNameTextBox != null)
    {
      firstName = firstNameTextBox.Text;
    }
    
    // Retrieve the new value for the author's last name from the row. 
    // In this example, the author's last name is in the third cell 
    // of the row (index 2).
    TextBox lastNameTextBox = (TextBox)row.Cells[2].FindControl("LastNameTextBox");
    
    String lastName = "";
    if(lastNameTextBox != null)
    {
      lastName = lastNameTextBox.Text;
    }
    
    // Because custom TemplateField field columns are used, parameters 
    // are not automatically created and passed to the data source control.
    // Create Parameter objects to represent the fields to update and 
    // add the Parameter objects to the UpdateParameters collection.
    Parameter lastNameParameter = new Parameter("au_lname", TypeCode.String, lastName);   
    Parameter firstNameParameter = new Parameter("au_fname", TypeCode.String, firstName);
    
    // Clear the UpdateParameters collection before adding the 
    // Parameter objects. Otherwise, there will be duplicate
    // parameters.
    AuthorsSqlDataSource.UpdateParameters.Clear();
    AuthorsSqlDataSource.UpdateParameters.Add(lastNameParameter);
    AuthorsSqlDataSource.UpdateParameters.Add(firstNameParameter);
    
  }
    
</script>

<head runat="server">
    <title>ButtonFieldBase CausesValidation Example</title>
</head>
<body>
  <form id="form1" runat="server">
  <div>

    <h3>ButtonFieldBase CausesValidation Example</h3>

    <!-- Populate the Columns collection declaratively. -->
    <asp:gridview id="AuthorsGridView" 
      datasourceid="AuthorsSqlDataSource"
      cellpadding="5"  
      autogeneratecolumns="false"
      datakeynames="au_id" 
      onrowcommand="AuthorsGridView_RowCommand"
      onrowupdating="AuthorsGridView_RowUpdating"  
      runat="server">

      <columns>
        <asp:buttonfield commandname="Edit"
          causesvalidation="false" 
          text="Edit" 
          headertext="Edit Author">
        </asp:buttonfield>

        <asp:buttonfield commandname="Update" 
          visible="false" 
          causesvalidation="true" 
          text="Update"
          validationgroup="NameGroup" 
          headertext="Update Author">
        </asp:buttonfield>

        <asp:templatefield headertext="Last Name">
          <itemtemplate>
            <%# Eval("au_lname") %>
          </itemtemplate>

          <edititemtemplate>
            <asp:textbox id="LastNameTextBox"
              text='<%# Eval("au_lname") %>'
              width="175" 
              runat="server" /><br />  

            <asp:RequiredFieldValidator ID="LastNameRequiredValidator"
              ControlToValidate="LastNameTextBox"
              ErrorMessage="Please enter a last name."
              ValidationGroup="NameGroup" 
              Runat="server" />

          </edititemtemplate>
        </asp:templatefield>

        <asp:templatefield headertext="First Name">
          <itemtemplate>
            <%# Eval("au_fname") %>
          </itemtemplate>

          <edititemtemplate>
            <asp:textbox id="FirstNameTextBox"
              text='<%# Eval("au_fname") %>'
              width="175" 
              runat="server" /><br />  

            <asp:RequiredFieldValidator ID="FirstNameRequiredValidator"
              ControlToValidate="FirstNameTextBox"
              ErrorMessage="Please enter a first name."
              ValidationGroup="NameGroup" 
              Runat="server" />

          </edititemtemplate>

        </asp:templatefield>
      </columns>

    </asp:gridview>

    <!-- This example uses Microsoft SQL Server and connects -->
    <!-- to the Pubs sample database.                        -->
    <asp:sqldatasource id="AuthorsSqlDataSource"  
      selectcommand="SELECT [au_id], [au_lname], [au_fname] FROM [authors]"
      updatecommand="UPDATE authors SET au_lname=@au_lname, au_fname=@au_fname WHERE (authors.au_id = @au_id)"
      connectionstring="server=localhost;database=pubs;integrated security=SSPI"
      runat="server">   
    </asp:sqldatasource>

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


<%@ Page language="VB" %>

<script runat="server">

  Sub AuthorsGridView_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs)
  
    ' If multiple ButtonField columns are used, use the
    ' CommandName property to determine which button was clicked.
    Select Case e.CommandName
    
      Case "Edit"
        AuthorsGridView.Columns(0).Visible = False
        AuthorsGridView.Columns(1).Visible = True
      Case "Update"
        AuthorsGridView.Columns(0).Visible = True
        AuthorsGridView.Columns(1).Visible = False
      Case Else
        ' Do nothing.
   
    End Select
    
  End Sub
  
  Sub AuthorsGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)
    
    ' Retrieve the row being edited.    
    Dim index As Integer = AuthorsGridView.EditIndex
    Dim row As GridViewRow = AuthorsGridView.Rows(index)
    
    ' Retrieve the new value for the author's first name from the row. 
    ' In this example, the author's first name is in the second cell 
    ' of the row (index 1). To get the value, first retrieve the TextBox
    ' that contains the value.
    Dim firstNameTextBox As TextBox = CType(row.Cells(1).FindControl("FirstNameTextBox"), TextBox)
    
    ' Make sure the control was found. 
    Dim firstName As String = ""
    If Not firstNameTextBox Is Nothing Then

      firstName = firstNameTextBox.Text
      
    End If
    
    ' Retrieve the new value for the author's last name from the row. 
    ' In this example, the author's last name is in the third cell 
    ' of the row (index 2).
    Dim lastNameTextBox As TextBox = CType(row.Cells(2).FindControl("LastNameTextBox"), TextBox)
    
    Dim lastName As String = ""
    If Not lastNameTextBox Is Nothing Then
    
      lastName = lastNameTextBox.Text
      
    End If
    
    ' Because custom TemplateField field columns are used, parameters 
    ' are not automatically created and passed to the data source control.
    ' Create Parameter objects to represent the fields to update and 
    ' add the Parameter objects to the UpdateParameters collection.
    Dim lastNameParameter As New Parameter("au_lname", TypeCode.String, lastName)
    Dim firstNameParameter As New Parameter("au_fname", TypeCode.String, firstName)
    
    ' Clear the UpdateParameters collection before adding the 
    ' Parameter objects. Otherwise, there will be duplicate
    ' parameters.
    AuthorsSqlDataSource.UpdateParameters.Clear()
    AuthorsSqlDataSource.UpdateParameters.Add(lastNameParameter)
    AuthorsSqlDataSource.UpdateParameters.Add(firstNameParameter)
    
  End Sub
    
</script>

<head runat="server">
    <title>ButtonFieldBase CausesValidation Example</title>
</head>
<body>
  <form id="form1" runat="server">
  <div>

    <h3>ButtonFieldBase CausesValidation Example</h3>

    <!-- Populate the Columns collection declaratively. -->
    <asp:gridview id="AuthorsGridView" 
      datasourceid="AuthorsSqlDataSource"
      cellpadding="5"  
      autogeneratecolumns="false"
      datakeynames="au_id" 
      onrowcommand="AuthorsGridView_RowCommand"
      onrowupdating="AuthorsGridView_RowUpdating"  
      runat="server">

      <columns>
        <asp:buttonfield commandname="Edit"
          causesvalidation="false" 
          text="Edit" 
          headertext="Edit Author">
        </asp:buttonfield>

        <asp:buttonfield commandname="Update" 
          visible="false" 
          causesvalidation="true" 
          text="Update"
          validationgroup="NameGroup" 
          headertext="Update Author">
        </asp:buttonfield>

        <asp:templatefield headertext="Last Name">
          <itemtemplate>
            <%# Eval("au_lname") %>
          </itemtemplate>

          <edititemtemplate>
            <asp:textbox id="LastNameTextBox"
              text='<%# Eval("au_lname") %>'
              width="175" 
              runat="server" /><br />  

            <asp:RequiredFieldValidator ID="LastNameRequiredValidator"
              ControlToValidate="LastNameTextBox"
              ErrorMessage="Please enter a last name."
              ValidationGroup="NameGroup" 
              Runat="server" />

          </edititemtemplate>
        </asp:templatefield>

        <asp:templatefield headertext="First Name">
          <itemtemplate>
            <%# Eval("au_fname") %>
          </itemtemplate>

          <edititemtemplate>
            <asp:textbox id="FirstNameTextBox"
              text='<%# Eval("au_fname") %>'
              width="175" 
              runat="server" /><br />  

            <asp:RequiredFieldValidator ID="FirstNameRequiredValidator"
              ControlToValidate="FirstNameTextBox"
              ErrorMessage="Please enter a first name."
              ValidationGroup="NameGroup" 
              Runat="server" />

          </edititemtemplate>

        </asp:templatefield>
      </columns>

    </asp:gridview>

    <!-- This example uses Microsoft SQL Server and connects -->
    <!-- to the Pubs sample database.                        -->
    <asp:sqldatasource id="AuthorsSqlDataSource"  
      selectcommand="SELECT [au_id], [au_lname], [au_fname] FROM [authors]"
      updatecommand="UPDATE authors SET au_lname=@au_lname, au_fname=@au_fname WHERE (authors.au_id = @au_id)"
      connectionstring="server=localhost;database=pubs;integrated security=SSPI"
      runat="server">   
    </asp:sqldatasource>

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

Opmerkingen

Gebruik deze indexeerfunctie om een DataControlField object op te halen uit de DataControlFieldCollection verzameling op de opgegeven index, met behulp van matrix-notatie.

Van toepassing op

Zie ook