如何将XML文件读取到Dictionary <String,List <String >>,其中包含空元素的空字符串

Question

我有一个xml文件,如:

<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>

和一个像这样的词典:

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

我正在读取XML文件,MyDict如:

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());

现在字典将包含:

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

但我的问题是我需要所有列表具有相同的计数.应为空条目添加空字符串,因此预期结果为:

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

如何修改LINQ查询？

请帮我用LINQ做这个.

提前致谢.

Answer 1

假设您希望在MyDict创建之后将其作为后处理步骤完成,基本思路将是:

1. 找出每个列表的大小应该是什么(基于最大列表的计数).
2. 根据需要使用空字符串填充每个列表,以使其达到正确的大小.

// 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));

这是一种返回具有所需特征的新词典而不改变原始集合的方法:

 // 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()
  );