The problem here is that the expression library is throwing an exception when given two arguments of mismatched nullability. Here’s a simple repro: Expression<Func<DateTime?>> ex1 = ()=>DateTime.Now; Expression<Func<DateTime>> ex2 = ()=>DateTime.Now; var ex3 = Expression.GreaterThan(ex1.Body, ex2.Body); It is not clear to me whether this is a bug or not; the rules of C# require that … Read more
var query = someList.Where(a => (someCondition)? a == “something” : true); so, if ‘someCondition’ is false, ‘Where’ will be skipped.
What is the possible use of StringWriter and StringReader, which cannot be done by StringBuilder itself? StringReader and StringWriter derive from TextReader and TextWriter respectively. So what they can do act as a TextReader or TextWriter instance, which string or StringBuilder cannot because they do not derive either of those types. What is the practical … Read more
Let’s dissect your code sample: filenames.SelectMany(f => Assembly.LoadFrom(f).GetCustomAttributes(typeof(PluginClassAttribute), true) .Cast<PluginClassAttribute>() .Select(a => a.PluginType) ).ToList(); So, we start off with a string[] called filenames. We invoke the SelectMany extension method on the array, and then we invoke ToList on the result: filenames.SelectMany( … ).ToList(); SelectMany takes a delegate as parameter, in this case the delegate must … Read more
If you provide your own get/set then you need to provide your own storage for the variable. private float _inverseMass; public float inverseMass { get { return _inverseMass; } set { _inverseMass = value; onMassChanged(); } }
Take the type/ID checking out of the recursion, so just have a “give me all the controls, recursively” method, e.g. public static IEnumerable<Control> GetAllControls(this Control parent) { foreach (Control control in parent.Controls) { yield return control; foreach(Control descendant in control.GetAllControls()) { yield return descendant; } } } That’s somewhat inefficient (in terms of creating lots … Read more
You will have to map the physicalPath to a virtualPath. Here is how you would do that. using System.Web.Configuration; //Reference the System.Web DLL (project needs to be using .Net 4.0 full, not client framework) public static Configuration OpenConfigFile(string configPath) { var configFile = new FileInfo(configPath); var vdm = new VirtualDirectoryMapping(configFile.DirectoryName, true, configFile.Name); var wcfm = … Read more
There’s nothing to say that the value of myEnum will be one of those values. Don’t mistake enums for being a restrictive set of values. It’s really just a named set of values. For example, I could call your method with: int x = Method((MyEnum) 127); What would you want that to do? If you … Read more
It can be done using LINQ ToDictionary() extension method: string s1 = “(colorIndex=3)(font.family=Helvicta)(font.bold=1)”; string[] t = s1.Split(new[] { ‘(‘, ‘)’ }, StringSplitOptions.RemoveEmptyEntries); Dictionary<string, string> dictionary = t.ToDictionary(s => s.Split(‘=’)[0], s => s.Split(‘=’)[1]); EDIT: The same result can be achieved without splitting twice: Dictionary<string, string> dictionary = t.Select(item => item.Split(‘=’)).ToDictionary(s => s[0], s => s[1]);
As mentioned, MIME magic is the only way to do this. Many platforms provide up-to-date and robust MIME magic files and code to do this efficiently. The only way to do this in .NET without any 3rd party code is to use FindMimeFromData from urlmon.dll. Here’s how: public static int MimeSampleSize = 256; public static … Read more