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Query a list in another list in C#

开发者 https://www.devze.com 2023-01-09 08:53 出处:网络
I have a class like that public class Tbl { public Lis开发者_JS百科t<Row> Rows {get; set;} } public class Row

I have a class like that

public class Tbl
{
    public Lis开发者_JS百科t<Row> Rows {get; set;}
}
public class Row
{
    public string Name {get; set;}
    public Value {get; set;}
}
//Using the class  
//Add rows to Tbl
Tbl t = new Tbl();
t.Rows.Add(new Row() {Name = "Row1", Value = "Row1Value"};
t.Rows.Add(new Row() {Name = "Row2", Value = "Row2Value"};
t.Rows.Add(new Row() {Name = "Row3", Value = "Row3Value"};

//Now I want to select the Row2 in this list, usually, I use this way
public Row GetRow(this Tbl t, string RowName)
{
    return t.Rows.Where(x => x.Name == RowName).FirstOrDefault();
}
Row r = t.GetRow("Row2");
//But I would like to use that way
Row r = t.Rows["Row2"];

How can I do that.

Thanks for every comments.


Extension properties do not exist, but you could use a wrapper around List<Row> and add an Indexer property to it.

public class RowList : List<Row> {

    public Row this[string key] {
        get { return this.Where( x => x.Name == key ).FirstOrDefault(); }
    }
}

public class Tbl
{
    public RowList Rows { get; set; }
}

Tbl t = new Tbl();
// ...
Row r = t.Rows["Row2"];


Use a string indexer in yout Tbl class

public Row this[string s]
{
    get
    {
        return Rows.Where(x => x.Name == s).FirstOrDefault();
    }
}

Then you use like:

Row r = t["Row2"] 


You'll need to add an indexed property to your Tbl type:

public class Tbl
{
    public List<Row> Rows { get; set; }

    public Row this[string name]
    {
        get
        {
            return Rows.Where(r => r.Name == name).FirstOrDefault();
        }
    }
}


I think what you need there is an Indexer, which would allow you to do t["Row2"] - I'm not sure how easily you could use that to do t.Rows["Row2"] though.


Add this to your Tbl class:

  public Row this[string name] {
     get { return Rows.Where(r => r.Name == name).FirstOrDefault(); }
  }
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