消息没有重新更新

本文关键字：更新 新更新 消息 | 更新日期: 2023-09-27 18:09:37

我为"People"类设置了两种"Description"，

  1. 具有Message:， Priority:和Tag:
    2. 的数据

  2. 没有这些数据

    List<People> lstPeople = new List<People>
{
    new People { Message = "[1y] Message: test messg1 Priority: top Tag: t1" },
    new People { Message = "without Message, Priority and Tag desc" }
};
var data = lstPeople;

我想提取"Message:"、"Priority:"answers"Tag:"之后的数据，并重新更新"People"类"Message"、"Priority"answers"Tag"的每个实体。

下面的代码更新"优先级"answers"标签"，但不更新"消息"。原因是什么呢?

    public class People
{
    const string ALERT_DESC_MARKER = "Message:";
    const string PRIORITY_MARKER = "Priority:";
    const string TAG_MARKER = "Tag:";
    private string _description;
    private string _tag;
    private string _priority;
    public string Message
    {
        get
        {
            if (_description.Contains(ALERT_DESC_MARKER) && _description.Contains(PRIORITY_MARKER))
                return _description ?? GetTextPart(_description, ALERT_DESC_MARKER, PRIORITY_MARKER).Trim();
            else
                return _description;
        }
        set
        {
            _description = value;
        }
    }
    public string Priority
    {
        get
        {
            if (_description.Contains(PRIORITY_MARKER) && _description.Contains(TAG_MARKER))
                return _priority = GetTextPart(_description, PRIORITY_MARKER, TAG_MARKER).Trim();
            else
                return _priority;
        }
        set
        {
            _priority = value;
        }
    }
    public string Tag
    {
        get
        {
            if (_description.Contains(TAG_MARKER))
                return _tag = GetTextPart(_description, TAG_MARKER, null).Trim();
            else
                return _tag;
        }
        set
        {
            _tag = value;
        }
    }
    private string GetTextPart(string text, string before, string after)
    {
        string result = null;
        int posBefore = text.IndexOf(before);
        if (after != null)
        {
            int posAfter = text.IndexOf(after);
            result = text.Remove(posAfter).Substring(posBefore + before.Length).TrimEnd();
        }
        else
            result = text.Substring(posBefore + before.Length);
        return result;
    }
}

消息没有重新更新

问题出在Message的getter。如文档所述:

? ?操作符称为空合并操作符。如果操作数不为空，则返回左操作数;否则返回右操作数

所以在你的例子中，如果_description不是null，你总是返回整个string。相反，如果满足此条件(_description != null)，则需要返回GetTextPart。这样的:

if (_description.Contains(ALERT_DESC_MARKER) && _description.Contains(PRIORITY_MARKER))
    return _description != null ? GetTextPart(_description, ALERT_DESC_MARKER, PRIORITY_MARKER).Trim() : _description;
编辑:

下面是您的测试示例:

List<People> lstPeople = new List<People>
{
    new People { Message = "[1y] Message: test messg1 Priority: top Tag: t1" },
    new People { Message = "without Message, Priority and Tag desc" }
};
var data = lstPeople;

foreach (var item in lstPeople)
{
    Console.WriteLine(item.Message);
    Console.WriteLine(item.Priority);
    Console.WriteLine(item.Tag);
}

输出第一项:

测试messg1

最高

t1

输出第二项:

不带Message、Priority和Tag desc

第二项Priority和Tag为空。

编辑2:

这是Message getter。我用来测试的其余代码与您发布的代码相同。注释掉的部分是你的旧版本

public string Message
{
    get
    {
        if (_description.Contains(ALERT_DESC_MARKER) && _description.Contains(PRIORITY_MARKER))
            return _description != null ? GetTextPart(_description, ALERT_DESC_MARKER, PRIORITY_MARKER).Trim(): _description;
        //if (_description.Contains(ALERT_DESC_MARKER) && _description.Contains(PRIORITY_MARKER))
        //    return _description ?? GetTextPart(_description, ALERT_DESC_MARKER, PRIORITY_MARKER).Trim();
        else
            return _description;
    }
    set
    {
        _description = value;
    }
}
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