如何将XML文件读取到字典< String，List&String>>空字符串为空元素 [英] How to read XML file to a Dictionary<String,List<String>> with empty strings for null elements

问题描述

我有一个xml文件，如：

I'm having an xml file like:

<root>
  <RowDetails RowName="A" ColumnSize="1">
    <ColumnDetails ColumnName="A1" />
  </RowDetails>
  <RowDetails RowName="B" ColumnSize="2">
    <ColumnDetails ColumnName="B1" />
    <ColumnDetails ColumnName="B2" />
  </RowDetails>
  <RowDetails RowName="C" ColumnSize="3">
    <ColumnDetails ColumnName="C1" />
    <ColumnDetails ColumnName="C2" />
    <ColumnDetails ColumnName="C3" />
  </RowDetails>
</root>

和一个字典如下：

Dictionary<String, List<String>>MyDict = new Dictioanary<String, List<String>>();

我正在将XML文件读入 MyDict 就像：

and i'm reading the XML file to MyDict is like:

XDocument XDoc = XDocument.Load(Application.StartupPath + @"\foo.xml");
MyDict = XDoc.Descendants("RowDetails").ToDictionary(X => X.Attribute("RowName").Value, 
                                                     X => X.Descendants("ColumnDetails")
                                                           .Select(Y => Y.Attribute("ColumnName").Value).ToList());

现在Dictionary将包含：

Now the Dictionary will contain:

"A"           { "A1" }
"B"           { "B1", "B2" }
"C"           { "C1", "C2", "C3" }

但我的问题是我需要所有的列表相同的计数。应为空条目添加空字符串，因此预期结果为：

but my problem is that I need all the list with same count. Empty string should be added for null entry, so the expected result is:

"A"           { "A1", "", "" }
"B"           { "B1", "B2", "" }
"C"           { "C1", "C2", "C3" }

如何修改我的LINQ查询？

How can I modify my LINQ query?

请帮我做使用LINQ。

Please help me to do this using LINQ.

提前感谢

推荐答案

假设你会就像这样做，在 MyDict 创建之后的后处理步骤中，基本思想是：

Assuming you would like this to be done as a post-processing step after MyDict is created, the basic idea would be:

1. 了解每个列表的大小应该如何（基于最大列表的计数）。


2. 将每个列表与空字符串，以使其达到正确的大小。

1. Find out what the size of each list should be (based on the count of the biggest list).
2. Pad each list with empty strings as required to bring it up to the right size.

---

---

// The required size is the count of the biggest list
var sizeRequired = MyDict.Values.Max(l => l.Count);

// Pad each list as necessary
foreach (var list in MyDict.Values)
    list.AddRange(Enumerable.Repeat(string.Empty, sizeRequired - list.Count));

这里有一种方法可以返回一个具有所需特征的新字典，而不使用原始集合：

Here's a way to return a new Dictionary with the required characteristics without mutating the original collection:

 // The required size is the count of the biggest list
var sizeRequired = MyDict.Values.Max(l => l.Count);

// Each string key should map to a key in the new dictionary
// Each List<string> value should map to a new list, padded as necessary.
var paddedDict = MyDict.ToDictionary
  (
     kvp => kvp.Key,
     kvp => kvp.Value
               .Concat(Enumerable.Repeat(string.Empty, sizeRequired - kvp.Value.Count))
               .ToList()
  );

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