not displayed when ItemsSource is initially set to a list and then set to Null

Oct 13, 2025 by windailys.com 17 views

Windows EmptyViewTemplate not displayed when ItemsSource is initially set to a list and then set to Null

Description

In a .NET MAUI application, when using a CollectionView with an ItemsSource initially set to a list, the EmptyViewTemplate is not displayed when the ItemsSource is subsequently set to None. However, if the ItemsSource is initially set to None, the EmptyViewTemplate is displayed correctly. This behavior is observed on Windows platforms, and it is essential to understand the correct usage of EmptyViewTemplate in CollectionView to avoid any confusion.

Understanding EmptyViewTemplate

The EmptyViewTemplate is a feature in CollectionView that allows developers to display a custom view when the ItemsSource is empty. It is a crucial aspect of user experience, as it provides a clear indication to the user that there is no data available. However, the correct usage of EmptyViewTemplate is not always straightforward, and this article aims to provide a detailed explanation of the issue at hand.

Steps to Reproduce

To reproduce the issue, follow these steps:

Launch the application on Windows by downloading and installing the CollectionViewSample.zip file from the provided link.
Tap the EmptyView/EmptyViewTemplate button to navigate to the CollectionView Control Page.
Tap the Options toolbar item to navigate to the Options Page, then select ItemsSource and EmptyViewTemplate.
Observe that the EmptyViewTemplate is not displayed.

Expected Behavior vs Actual Behavior

The expected behavior is that the EmptyViewTemplate should be displayed when the ItemsSource is set to None, regardless of the initial state of the ItemsSource. However, the actual behavior is that the EmptyViewTemplate is not displayed when the ItemsSource is initially set to a list and then changed to None.

Link to public reproduction project repository

Unfortunately, the link to the public reproduction project repository is not provided.

Version with bug

The version with the bug is 9.0.40 SR4.

Is this a regression from previous behavior?

It is not clear whether this is a regression from previous behavior, as the issue was not tested on other versions.

Last version that worked well

Unfortunately, the last version that worked well is not provided.

Affected platforms

The affected platform is Windows.

Affected platform versions

Unfortunately, the affected platform versions are not provided.

Did you find any workaround?

Unfortunately, no workaround is provided.

Relevant log output

Analysis of the Issue

The issue at hand is a complex one, and it requires a deep understanding of the CollectionView control and its behavior. The problem arises when the ItemsSource is initially set to a list and then changed to None. In this scenario, the EmptyViewTemplate is not displayed, which is the expected behavior.

However, if the ItemsSource is initially set to None, the EmptyViewTemplate is displayed correctly. This suggests that the issue is related to the way the CollectionView control handles the ItemsSource property.

Possible Causes

There are several possible causes for this issue:

Incorrect usage of ItemsSource: The ItemsSource property might be set incorrectly, leading to the EmptyViewTemplate not being displayed.
CollectionView control bug: The CollectionView control might have a bug that prevents the EmptyViewTemplate from being displayed when the ItemsSource is changed to None.
Platform-specific issue: The issue might be specific to the Windows platform and might not be present on other platforms.

Solution

To solve this issue, the following steps can be taken:

Check the usage of ItemsSource: Ensure that the ItemsSource property is set correctly and that it is not causing the issue.
Update the CollectionView control: Update the CollectionView control to the latest version to see if the issue is resolved.
Test on other platforms: Test the application on other platforms to see if the issue is specific to the Windows platform.

Conclusion

In conclusion, the issue of the EmptyViewTemplate not being displayed when the ItemsSource is initially set to a list and then changed to None is a complex one. It requires a deep understanding of the CollectionView control and its behavior. By analyzing the possible causes and taking the necessary steps, the issue can be resolved, and the EmptyViewTemplate can be displayed correctly.

Recommendations

Based on the analysis of the issue, the following recommendations can be made:

Use the latest version of the CollectionView control: Update the CollectionView control to the latest version to ensure that the issue is resolved.
Test on other platforms: Test the application on other platforms to see if the issue is specific to the Windows platform.
Check the usage of ItemsSource: Ensure that the ItemsSource property is set correctly and that it is not causing the issue.

By following these recommendations, the issue can be resolved, and the EmptyViewTemplate can be displayed correctly.
Windows EmptyViewTemplate not displayed when ItemsSource is initially set to a list and then set to Null: Q&A

Q: What is the EmptyViewTemplate in CollectionView?

A: The EmptyViewTemplate is a feature in CollectionView that allows developers to display a custom view when the ItemsSource is empty. It is a crucial aspect of user experience, as it provides a clear indication to the user that there is no data available.

Q: Why is the EmptyViewTemplate not displayed when the ItemsSource is initially set to a list and then changed to None?

A: The issue arises when the ItemsSource is initially set to a list and then changed to None. In this scenario, the EmptyViewTemplate is not displayed, which is the expected behavior. However, if the ItemsSource is initially set to None, the EmptyViewTemplate is displayed correctly.

Q: What are the possible causes of this issue?

A: There are several possible causes for this issue:

Incorrect usage of ItemsSource: The ItemsSource property might be set incorrectly, leading to the EmptyViewTemplate not being displayed.
CollectionView control bug: The CollectionView control might have a bug that prevents the EmptyViewTemplate from being displayed when the ItemsSource is changed to None.
Platform-specific issue: The issue might be specific to the Windows platform and might not be present on other platforms.

Q: How can I solve this issue?

A: To solve this issue, the following steps can be taken:

Check the usage of ItemsSource: Ensure that the ItemsSource property is set correctly and that it is not causing the issue.
Update the CollectionView control: Update the CollectionView control to the latest version to see if the issue is resolved.
Test on other platforms: Test the application on other platforms to see if the issue is specific to the Windows platform.

Q: What are the recommendations for resolving this issue?

A: Based on the analysis of the issue, the following recommendations can be made:

Use the latest version of the CollectionView control: Update the CollectionView control to the latest version to ensure that the issue is resolved.
Test on other platforms: Test the application on other platforms to see if the issue is specific to the Windows platform.
Check the usage of ItemsSource: Ensure that the ItemsSource property is set correctly and that it is not causing the issue.

Q: Is this a regression from previous behavior?

A: It is not clear whether this is a regression from previous behavior, as the issue was not tested on other versions.

Q: What is the expected behavior of the EmptyViewTemplate?

A: The expected behavior of the EmptyViewTemplate is that it should be displayed when the ItemsSource is set to None, regardless of the initial state of the ItemsSource.

Q: What is the actual behavior of the EmptyViewTemplate?

A: The actual behavior of the EmptyViewTemplate is that it is not displayed when the ItemsSource is initially set to a list and then changed to None.

Q: Can I use a workaround to resolve this issue?

A: Unfortunately, no workaround is provided.

Q: What are the affected platforms?

A: The affected platform is Windows.

Q: What are the affected platform versions?

A: Unfortunately, the affected platform versions are not provided.

Q: Can I get help from the community?

A: Unfortunately, the link to the public reproduction project repository is not provided.

Q: Can I get help from the support team?

A: Unfortunately, no response is provided.

Q: What are the next steps to resolve this issue?

A: The next steps to resolve this issue are to:

Check the usage of ItemsSource: Ensure that the ItemsSource property is set correctly and that it is not causing the issue.
Update the CollectionView control: Update the CollectionView control to the latest version to see if the issue is resolved.
Test on other platforms: Test the application on other platforms to see if the issue is specific to the Windows platform.