[WPF] - Accéder aux controls directement sans passer par le binding

26.04.2007

Soit :

Ici j’ai une TextBox qui a un Template simpliste pour bien comprendre

(Le template comprend donc une grille avec une TextBox, mais on pourrait facilement ajouter par exemple une image et d’autres controls)

<Window x:Class="WPFFindNameAndVisualTest.Window1"

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Title="WPFFindNameAndVisualTest" Height="300" Width="300"

>

<Button Name="btnTestFindName" Click="btnTestFindName_Click" Height="23" Width="75">Test FindName()</Button>

<Button Name="btnTestVisual" Click="btnTestVisual_Click" Height="23" Width="75">Test Visual</Button>

<TextBox.Template>

</Grid>

</ControlTemplate>

</TextBox.Template>

</TextBox>

</StackPanel>

</Window>

1 - FrameworkElement.FindName()

Il faut que l’élément soit declaré côté window.g.cs pour réussir à le trouver

public void btnTestFindName_Click(object e, RoutedEventArgs args)

{

object wantedNode = StackPanel1.FindName("txtTestFindName");

if (wantedNode is TextBox)

{

TextBox wantedChild = wantedNode as TextBox;

wantedChild.Text = "trouvé";

}

Window1.g.cs

//------------------------------------------------------------------------------

// <auto-generated>

// Ce code a été généré par un outil.

// Version du runtime :2.0.50727.42

//

// Les modifications apportées à ce fichier peuvent provoquer un comportement incorrect et seront perdues si

// le code est régénéré.

// </auto-generated>

//------------------------------------------------------------------------------

using System;

using System.Windows;

using System.Windows.Automation;

using System.Windows.Controls;

using System.Windows.Controls.Primitives;

using System.Windows.Data;

using System.Windows.Documents;

using System.Windows.Ink;

using System.Windows.Input;

using System.Windows.Markup;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Media.Effects;

using System.Windows.Media.Imaging;

using System.Windows.Media.Media3D;

using System.Windows.Media.TextFormatting;

using System.Windows.Navigation;

using System.Windows.Shapes;

namespace WPFFindNameAndVisualTest {

///<summary>

/// Window1

///</summary>

public partial class Window1 : System.Windows.Window, System.Windows.Markup.IComponentConnector {

internal System.Windows.Controls.StackPanel StackPanel1;

internal System.Windows.Controls.Button btnTestFindName;

internal System.Windows.Controls.TextBox txtTestFindName;

internal System.Windows.Controls.Button btnTestVisual;

internal System.Windows.Controls.TextBox txtTemplate;

private bool _contentLoaded;

///<summary>

/// InitializeComponent

///</summary>

[System.Diagnostics.DebuggerNonUserCodeAttribute()]

public void InitializeComponent() {

if (_contentLoaded) {

return;

}

_contentLoaded = true;

System.Uri resourceLocater = new System.Uri("/WPFFindNameAndVisualTest;component/window1.xaml", System.UriKind.Relative);

System.Windows.Application.LoadComponent(this, resourceLocater);

}

[System.Diagnostics.DebuggerNonUserCodeAttribute()]

[System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]

[System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]

void System.Windows.Markup.IComponentConnector.Connect(int connectionId, object target) {

switch (connectionId)

{

case 1:

this.StackPanel1 = ((System.Windows.Controls.StackPanel)(target));

return;

case 2:

this.btnTestFindName = ((System.Windows.Controls.Button)(target));

#line 7 "....Window1.xaml"

this.btnTestFindName.Click += new System.Windows.RoutedEventHandler(this.btnTestFindName_Click);

#line default

#line hidden

return;

case 3:

this.txtTestFindName = ((System.Windows.Controls.TextBox)(target));

return;

case 4:

this.btnTestVisual = ((System.Windows.Controls.Button)(target));

#line 12 "....Window1.xaml"

this.btnTestVisual.Click += new System.Windows.RoutedEventHandler(this.btnTestVisual_Click);

#line default

#line hidden

return;

case 5:

this.txtTemplate = ((System.Windows.Controls.TextBox)(target));

return;

}

this._contentLoaded = true;

}

2 – FrameworkTemplate.FindName()

Permet acceder aux controls d’un template

Donc dans mon cas cela donnerait par exemple pour accéder à la TextBox txtTestVisual :

public void btnTestFindName_Click(object e, RoutedEventArgs args)

{

Grid grid = this.txtTemplate.Template.FindName("Grid1", this.txtTemplate) as Grid;

TextBox oTextBox = grid.FindName("txtTestVisual") as TextBox;

oTextBox.Text = "trouvé grâce à FrameworkTemplate.FindName()";

}

> Thomas Lebrun explique trés bien cela sur son blog

[WPF] Comment accéder aux contrôles existants dans un Template ?

http://blogs.codes-sources.com/tom/archive/2007/04/26/wpf-comment-acc-der-aux-contr-les-existants-dans-un-template.aspx

3 – VisualTreeHelper

Permet accéder aux tous controls même ceux d’un template

public void btnTestVisual_Click(object e, RoutedEventArgs args)

{

EnumVisual(txtTemplate);

}

public void EnumVisual(Visual oVisual)

{

for (int nVisualChildrenCount = 0; nVisualChildrenCount < VisualTreeHelper.GetChildrenCount(oVisual); nVisualChildrenCount++)

{

Visual childVisual;

childVisual = (Visual)VisualTreeHelper.GetChild(oVisual, nVisualChildrenCount);

if (childVisual is TextBox)

{

TextBox wantedChild = childVisual as TextBox;

//

if (wantedChild.Name == "txtTestVisual")

{

wantedChild.Text = "trouvé";

}

//

EnumVisual(childVisual);

}

Liens

FrameworkElement.FindName Method

http://msdn2.microsoft.com/en-us/library/system.windows.frameworkelement.findname.aspx

VisualTreeHelper Class

http://msdn2.microsoft.com/en-us/library/system.windows.media.visualtreehelper.aspx