Searching though values of a dictionary

I have a dictionary that contains Product values with properties like description. In a textbox1_textchanged handler, I want to search the Products in the dictionary that has certain text within the description.

I've tried this:

var values = (from pv in mydictionary
              where pv.Value.description.Contains(textBox1.Text)
              select pv.Value);

This code isn't working because the second key I pressed values var values is empty.

All the exa开发者_开发问答mples I found are searching through the keys but I need to search through the values of the dictionary.

What you have isn't valid code however. You are trying to filter the values that have a certain description but you're missing a key element. You need to add the where clause to complete it.

var values =
    from pv in mydictionary
    where pv.Value.description.Contains(textBox1.Text)
    select pv.Value;

A better way to write this however would be to just look at the values of the dictionary.

var values =
    from value in mydictionary.Values // Note: we're looking through the values only,
                                      // not all the key/value pairs in the dictionary
    where value.description.Contains(textBox1.Text)
    select value;

To make it case-insensitive, you could try using String.IndexOf() since it's one of the few comparisons that could do the search ignoring the case.

var values =
    from value in mydictionary.Values
    where value.description
               .IndexOf(textBox1.Text, StringComparison.OrdinalIgnoreCase) != -1
               // any value that isn't `-1` means it contains the text
               // (or the description was empty)
    select value;

Try

var values =  mydictionary.Where(k => k.Value.description.Contains(textBox1.Text))
                          .Select(k => k.Value);

Change the where clause to:

where value != null && value.description != null && value.description.Contains(textBox1.Text) 

One other thing you may want to consider is that the string.Contains method will do a case sensitive search.

var str = "The quick brown fox blah";
var test1 = "quick";
var test2 = "Quick";

Console.WriteLine(string.Format("{0} CONTAINS {1} = {2}", str, test1, str.Contains(test1)));

Console.WriteLine(string.Format("{0} CONTAINS {1} = {2}", str, test2, str.Contains(test2)));

//Output
The quick brown fox blah CONTAINS quick = True
The quick brown fox blah CONTAINS Quick = False

If you cant a case insensitive search so that both of the above would return true you should put the strings in lower case first ...

Console.WriteLine(string.Format("{0} CONTAINS {1} = {2}", str, test1, str.ToLower().Contains(test1.ToLower())));

Console.WriteLine(string.Format("{0} CONTAINS {1} = {2}", str, test2, 
str.ToLower().Contains(test2.ToLower())));

//Output
The quick brown fox blah CONTAINS quick = True
The quick brown fox blah CONTAINS Quick = True