predicatebuilder

I'm beginning to use LinqKit 's PredicateBuilder to create predicate's with OR conditions which is not possible with Linq expressions. The problem I'm facing is if I begin with PredicateBuilder.True<MyEntity>() it returns all rows and if I begin with PredicateBuilder.False<MyEntity>() it returns non rows , apart from what expressions I use! look at the code below: var pre = PredicateBuilder.True<MyEntity>(); pre.And(m => m.IsActive == true); using (var db = new TestEntities()) { var list = db.MyEntity.AsExpandable().Where(pre).ToList(); dataGridView1.DataSource = list; } It should return the

Hi i want to create a list based on the search string using predicate expressions. I have a list of type products contains different names. List<products> list1 = new List<products>(); list1.Add(new products("sowmya")); list1.Add(new products("Jane")); list1.Add(new products("John")); list1.Add(new products("kumar")); list1.Add(new products("ramya")); listBox1.ItemsSource = list1; Now i want to filter the content based on user input.User will enter n no of strings with '+' as separator. After receiving the strings i will pass them to predicate object like this private void textBox1_KeyDown

I am using Xcode 4, and I can't find a way to work with the graphical predicate builder. Is it still there? How do I use it? Where is the documentation on this? Thanks In XCode 4, highlight your model, then: Choose Editor -> Add Fetch Request Then highlight it (rename if you like). The Predicate Builder is in the right pane: 来源： https://stackoverflow.com/questions/5629349/graphical-predicate-builder-in-xcode-4-with-core-data

I needed to build a dynamic filter and I wanted to keep using entities. Because of this reason I wanted to use the PredicateBuilder from albahari. I created the following code: var invoerDatums = PredicateBuilder.True<OnderzoeksVragen>(); var inner = PredicateBuilder.False<OnderzoeksVragen>(); foreach (var filter in set.RapportInvoerFilter.ToList()) { if(filter.IsDate) { var date = DateTime.Parse(filter.Waarde); invoerDatums = invoerDatums.Or(o => o.Van >= date && o.Tot <= date); } else { string temp = filter.Waarde; inner = inner.Or(o => o.OnderzoekType == temp); } } invoerDatums =

C# in a Nutshell has a free class called PredicateBuilder which constructs LINQ predicates piece by piece available here . Here's an extract of the method which adds a new expression to the predicate. Could someone explain it? (I have seen this question , I don't want a general answer like there. I am looking for a specific explanation of how Expression.Invoke and Expression.Lambda build the new expression). public static Expression<Func<T, bool>> And<T> (this Expression<Func<T, bool>> expr1, Expression<Func<T, bool>> expr2) { var invokedExpr = Expression.Invoke (expr2, expr1.Parameters.Cast