Image Source Converter

/ By / In C#, WPF / 2 Comments

Each time I have the need for an image converter for a WPF application, I end up searching the web looking for a sample, so this time, I’m putting a sample somewhere I can find it again easily.  Below is a basic IValueConverter implementation to convert a file name into a BitmapImage located in an images folder.

Code for Sample Project

public class IconImageConverter : IValueConverter
{
    public object Convert(object value, 
                       Type targetType, 
                       object parameter, 
                       System.Globalization.CultureInfo culture)
   {
      // if value isn't null, we can safely do the conversion. 
      if (value != null)
      {
          string imageName = value.ToString();
          Uri uri = new Uri(String.Format("/Images/{0}", imageName), 
                                UriKind.Relative);
          return new BitmapImage(uri);
      }
      return null;
   }
    public object ConvertBack(object value, 
                         Type targetType, 
                         object parameter, 
                         System.Globalization.CultureInfo culture)
    {
       throw new NotImplementedException();
    }
}

C# Extension Method Example

/ By / In C# / Leave Comment

I was telling a friend of mine about extension methods and created this one not much later, so I thought I’d post it, for him and anybody else that it could help.
 
This first snippet of code is a static class that has my extension method called GetElementName defined inside of it.  GetElementName takes two arguments.  The first is defined with “this XElement parentElement”.  The “this” keyword is there to specify the type for which the method is defined (in this case XElement).  The second parameter is defined with “string name” which is the name of the child element I’m looking for.
 

    4     /// <summary>

    5     /// Gets the case-sensitive LocalName of a child element.

    6     /// </summary>

    7     /// <param name="parentElement">XElement object to search through</param>

    8     /// <param name="name">The (case insensitive) LocalName of the child element you are looking for</param>

    9     /// <returns>String containing the LocalName of the XName child elements</returns>

   10     public static class MyCustomExtensions

   11     {

   12         public static string GetChildElementName(this XElement parentElement, string name)

   13         {

   16             var children = from c in parentElement.Elements()

   17                            where c.Name.LocalName.ToLower() == name.ToLower()

   18                            select c.Name;

   19             if (children.Count() > 0)

   20                 { return children.First().LocalName; }

   21             else

   22                 { return String.Empty; }

   23         }

   24     }

 

Now to use the extension method, I can just use the GetChildElementName method like it was always a part of the XElement class as long as I have a reference to the namespace that the MyCustomExtensions class is inside of.  I’ll have intellisense available for me and everything.

   15             File Defined somewhere as test.xml

   16             <Test>

   17                 <Path>http://www.google.com</Path>

   18                 <Path>http://www.bing.com</Path>

   19                 <Path>http://www.yahoo.com</Path>

   20             </Test>

   21             */

   22             XElement myTestElement = XElement.Load("test.xml");

   23 

   24             // Use GetChildElementName() to get the name of "Path" in case I can’t trust what case was used

   25             string name = myTestElement.GetChildElementName("path");

   26             IEnumerable<XElement> children = myTestElement.Elements(name);