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| 1 | +--- |
| 2 | +title: Accessing Controls Inside Dynamic Popup Loaded from DataTemplate in ResourceDictionary |
| 3 | +description: Learn how to dynamically load Popup content from a DataTemplate in a ResourceDictionary in UI for .NET MAUI and update the controls inside. |
| 4 | +type: how-to |
| 5 | +page_title: Updating Controls Inside Popup Loaded Dynamically from DataTemplate in ResourceDictionary |
| 6 | +meta_title: Updating Controls Inside Popup Loaded Dynamically from DataTemplate in ResourceDictionary |
| 7 | +slug: accessing-controls-inside-dynamic-radpopup-data-template |
| 8 | +tags: popup, datatemplate, radpopup, maui, binding |
| 9 | +res_type: kb |
| 10 | +--- |
| 11 | + |
| 12 | +## Environment |
| 13 | + |
| 14 | +| Version | Product | Author | |
| 15 | +| --- | --- | ---- | |
| 16 | +| 11.0.1 | Popup for .NET MAUI | [Dobrinka Yordanova](https://www.telerik.com/blogs/author/dobrinka-yordanova) | |
| 17 | + |
| 18 | +## Description |
| 19 | + |
| 20 | +I want to load a `RadPopup` dynamically using a `DataTemplate` defined in a `ResourceDictionary` and access or update the controls (e.g., `Label`) inside the template. However, accessing controls using `x:Name` is not working. I need a solution to update the control's properties, such as the `Text` property of a `Label`, when the popup opens. |
| 21 | + |
| 22 | +This knowledge base article also answers the following questions: |
| 23 | +- How to bind and update controls in a `RadPopup` `DataTemplate` in .NET MAUI? |
| 24 | +- How to dynamically modify the content of `RadPopup` in .NET MAUI? |
| 25 | +- How to set control properties inside `RadPopup` using bindings or code? |
| 26 | + |
| 27 | +## Solution |
| 28 | + |
| 29 | +To achieve this, you can use one of two approaches: |
| 30 | +* [Binding the controls to a `ViewModel`](#option-1-using-binding-with-viewmodel) |
| 31 | +* [Programmatically accessing the controls inside the `DataTemplate`.](#option-2-accessing-controls-programmatically) |
| 32 | + |
| 33 | +### Option 1: Using Binding with ViewModel |
| 34 | + |
| 35 | +Use bindings to update the control properties inside the `DataTemplate`. Bind the `Label`'s `Text` property to a `ViewModel` and ensure the binding mode is set to `TwoWay`. |
| 36 | + |
| 37 | +**1.** Define a `ViewModel` with a property for binding: |
| 38 | + |
| 39 | +```csharp |
| 40 | +public class ViewModel : NotifyPropertyChangedBase |
| 41 | +{ |
| 42 | + private string myValue; |
| 43 | + |
| 44 | + public ViewModel() |
| 45 | + { |
| 46 | + this.myValue = "hello"; |
| 47 | + } |
| 48 | + |
| 49 | + public string MyValue |
| 50 | + { |
| 51 | + get => this.myValue; |
| 52 | + set => this.UpdateValue(ref this.myValue, value); |
| 53 | + } |
| 54 | +} |
| 55 | +``` |
| 56 | + |
| 57 | +**2.** Set the `BindingContext` in your code-behind: |
| 58 | + |
| 59 | +```csharp |
| 60 | +public partial class MainPage : ContentPage |
| 61 | +{ |
| 62 | + ViewModel vm; |
| 63 | + |
| 64 | + public MainPage() |
| 65 | + { |
| 66 | + InitializeComponent(); |
| 67 | + this.vm = new ViewModel(); |
| 68 | + this.BindingContext = this.vm; |
| 69 | + } |
| 70 | + |
| 71 | + private void CheckBoxIsCheckedChanged(object sender, IsCheckedChangedEventArgs e) |
| 72 | + { |
| 73 | + if (e.NewValue == true) |
| 74 | + { |
| 75 | + this.popup.IsOpen = true; |
| 76 | + this.vm.MyValue = "value changed"; |
| 77 | + } |
| 78 | + } |
| 79 | +} |
| 80 | +``` |
| 81 | + |
| 82 | +**3.** Define the `DataTemplate` in XAML and bind the `Label`'s `Text` property: |
| 83 | + |
| 84 | +```xml |
| 85 | +<DataTemplate x:Key="PopupTemplate"> |
| 86 | + <telerik:RadBorder CornerRadius="8" |
| 87 | + BackgroundColor="#F9F9F9" |
| 88 | + BorderColor="Red" |
| 89 | + BorderThickness="1" |
| 90 | + WidthRequest="300" |
| 91 | + Padding="12"> |
| 92 | + <VerticalStackLayout Spacing="8"> |
| 93 | + <Label Text="{Binding MyValue, Mode=TwoWay}" /> |
| 94 | + </VerticalStackLayout> |
| 95 | + </telerik:RadBorder> |
| 96 | +</DataTemplate> |
| 97 | +``` |
| 98 | + |
| 99 | +### Option 2: Accessing Controls Programmatically |
| 100 | + |
| 101 | +Directly access the controls inside the `DataTemplate` programmatically and update their properties. |
| 102 | + |
| 103 | +**1.** Define the `DataTemplate` in XAML: |
| 104 | + |
| 105 | +```xml |
| 106 | +<DataTemplate x:Key="PopupTemplate"> |
| 107 | + <telerik:RadBorder CornerRadius="8" |
| 108 | + BackgroundColor="#F9F9F9" |
| 109 | + BorderColor="Red" |
| 110 | + BorderThickness="1" |
| 111 | + WidthRequest="300" |
| 112 | + Padding="12"> |
| 113 | + <VerticalStackLayout Spacing="8"> |
| 114 | + <Label /> |
| 115 | + </VerticalStackLayout> |
| 116 | + </telerik:RadBorder> |
| 117 | +</DataTemplate> |
| 118 | +``` |
| 119 | + |
| 120 | +**2.** In the code-behind, dynamically load the content and update the control properties: |
| 121 | + |
| 122 | +```csharp |
| 123 | +private void CheckBoxIsCheckedChanged(object sender, IsCheckedChangedEventArgs e) |
| 124 | +{ |
| 125 | + if (e.NewValue == true) |
| 126 | + { |
| 127 | + this.popup.IsOpen = true; |
| 128 | + var dataTemplate = this.myPage.Resources["PopupTemplate"] as DataTemplate; |
| 129 | + |
| 130 | + var popupcontent = dataTemplate.CreateContent() as View; |
| 131 | + this.popup.Content = popupcontent; |
| 132 | + |
| 133 | + List<IVisualTreeElement> items = (List<IVisualTreeElement>)this.popup.Content.GetVisualTreeDescendants(); |
| 134 | + foreach (IVisualTreeElement myControl in items) |
| 135 | + { |
| 136 | + if (myControl is Label) |
| 137 | + { |
| 138 | + Label control = (Label)myControl; |
| 139 | + control.Text = "popup content has been changed when opened"; |
| 140 | + return; |
| 141 | + } |
| 142 | + } |
| 143 | + } |
| 144 | +} |
| 145 | +``` |
| 146 | + |
| 147 | +### Key Considerations: |
| 148 | + |
| 149 | +- Accessing controls inside a `DataTemplate` using `x:Name` is not possible due to the general behavior of the MAUI framework. |
| 150 | +- Use bindings if you want to follow MVVM principles. |
| 151 | +- For direct control access, ensure the `DataTemplate` content is created and assigned to the popup before attempting to modify controls. |
| 152 | + |
| 153 | +## See Also |
| 154 | + |
| 155 | +- [.NET MAUI Popup Documentation](https://docs.telerik.com/devtools/maui/controls/popup/overview) |
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