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如何使用空字符串将XML文件读取到字典中

dictionary linq xml c#

Thorin Oakenshield · 技术社区 · 14 年前

我有一个XML文件,比如:

<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>

还有字典,比如:

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

我正在将XML文件读取到 MyDict 就像:

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相同计数的列表。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" }

如何修改我的LINQ查询?

请帮我用LINQ来做这个。

事先谢谢。

3 回复 | 直到 14 年前

Ani 14 年前

MyDict

// 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));

 // 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()
  );

Merlyn Morgan-Graham 14 年前

IEnumerable<T>

public static class IEnumerableExtensions
{
    public static IEnumerable<TSource> PadIfFewerThan<TSource>(
        this IEnumerable<TSource> items,
        int size, TSource padValue = default(TSource))
    {
        int count = 0;

        foreach (var item in items)
        {
            ++count;
            yield return item;
        }

        foreach (var index in Enumerable.Range(count, size - count))
            yield return padValue;
    }
}

var dictionary = doc.Descendants("RowDetails")
    .ToDictionary(
        x => x.Attribute("RowName").Value,
        x => x.Descendants("ColumnDetails")
            .Select(y => y.Attribute("ColumnName").Value)
            .PadIfFewerThan(3, "")
        );

foreach (var entry in dictionary)
    Console.WriteLine(@"""{0}""    {{""{1}""}}",
        entry.Key,
        string.Join(@""",""", entry.Value)
        );

Dictionary<string, List<string>> Dictionary<string, IEnumerable<string>> .ToList()

var dictionary = doc.Descendants("RowDetails")
    .ToDictionary(
        x => x.Attribute("RowName").Value,
        x => x.Descendants("ColumnDetails")
            .Select(y => y.Attribute("ColumnName").Value)
            .PadIfFewerThan(3)
            .ToList()
        );

-1

Remus 14 年前