bug(Cascader): should display Empty after click Clearable button

[ArgoZhang]

should display Empty after click Clearable button

Summary of the changes (Less than 80 chars)

简单描述你更改了什么, 不超过80个字符；如果有关联 Issue 请在下方填写相关编号

Description

fixes #5127

Regression?

• Yes
• No

[If yes, specify the version the behavior has regressed from]

[是否影响老版本]

Risk

• High
• Medium
• Low

[Justify the selection above]

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• Merge the latest code from the main branch

Summary by Sourcery

Bug Fixes:

• Fix an issue where the cascader component would not display "Empty" after clicking the clear button.

[sourcery-ai]

Reviewer's Guide by Sourcery

This PR fixes a bug in the Cascader component where clicking the clear button would not display "Empty". The fix involves updating the SetDefaultValue method in Cascader.razor.cs to set CurrentValueAsString to an empty string when clearing the selection. A corresponding unit test in CascaderTest.cs is updated to reflect this change.

Sequence diagram for Cascader clear button interaction

sequenceDiagram
    actor User
    participant Cascader
    User->>Cascader: Click clear button
    Cascader->>Cascader: SetDefaultValue()
    Note right of Cascader: Set CurrentValueAsString to empty
    Cascader->>Cascader: RefreshDisplayText()
    Cascader-->>User: Display empty text

Loading

State diagram for Cascader value clearing

stateDiagram-v2
    [*] --> HasValue: Initial state with value
    HasValue --> Empty: Click clear button
    Empty --> HasValue: Select new value
    Empty --> [*]
    HasValue --> [*]

Loading

File-Level Changes

Change	Details	Files
Set CurrentValueAsString to empty string when clearing selection	Modified the SetDefaultValue method to set CurrentValueAsString to an empty string instead of the first item's value when clearing the selection.	src/BootstrapBlazor/Components/Cascader/Cascader.razor.cs
Update unit test for clearing selection	Modified the assertion in SetDefaultValue_Ok test to expect an empty string for Value after clearing the selection.	test/UnitTest/Components/CascaderTest.cs

Assessment against linked issues

Issue	Objective	Addressed	Explanation
#5127	When the Clearable button is clicked, the Cascader should display Empty	✅
#5127	Ensure that the default value is set to an empty string when clearing the Cascader	✅

Possibly linked issues

• bug(Cascader): should display Empty after click Clearable button #5127: The PR fixes the issue by setting CurrentValueAsString to an empty string when the Clearable button is clicked.

---

Tips and commands

Interacting with Sourcery

• Trigger a new review: Comment @sourcery-ai review on the pull request.
• Continue discussions: Reply directly to Sourcery's review comments.
• Generate a GitHub issue from a review comment: Ask Sourcery to create an
  issue from a review comment by replying to it.
• Generate a pull request title: Write @sourcery-ai anywhere in the pull
  request title to generate a title at any time.
• Generate a pull request summary: Write @sourcery-ai summary anywhere in
  the pull request body to generate a PR summary at any time. You can also use
  this command to specify where the summary should be inserted.

Customizing Your Experience

Access your dashboard to:

• Enable or disable review features such as the Sourcery-generated pull request
  summary, the reviewer's guide, and others.
• Change the review language.
• Add, remove or edit custom review instructions.
• Adjust other review settings.

Getting Help

• Contact our support team for questions or feedback.
• Visit our documentation for detailed guides and information.
• Keep in touch with the Sourcery team by following us on X/Twitter, LinkedIn or GitHub.

[sourcery-ai]

Hey @ArgoZhang - I've reviewed your changes - here's some feedback:

Overall Comments:

• Please complete all relevant sections in the PR template, particularly regarding documentation updates, demo updates, and verification steps. This helps maintain project quality and smooth review process.

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

---

Sourcery is free for open source - if you like our reviews please consider sharing them ✨

• X
• Mastodon
• LinkedIn
• Facebook

_{Help me be more useful! Please click 👍 or 👎 on each comment and I'll use the feedback to improve your reviews.}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (3d46f4e) to head (2b21699).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #5128   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          634       634           
  Lines        28174     28174           
  Branches      4041      4040    -1     
=========================================
  Hits         28174     28174           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.