I have the following in VB:
Dim sources = From source In importSources Select New With _
{.Type = source.Key, .Source = source.Value.Name}
dgridSourceFiles.DataSource = sources
[code]....
Is it possible to retrieve the index number of an item/key in a Dictionary(Of TKey, TValue) object?
View 13 RepliesIs there any way to do the same in VB.NET?[code]...
View 1 RepliesI want to create an implementation of the IDictionary(Of TKey, TValue) interface to provide some wrapper functionality.
[code]...
The error is Interface 'System.Collections.Generic.ICollection(Of T) is not implemented by this class. I am not sure what to do about this error. I don't even really understand it. I trade to change the (Of T) to (Of TValue) but that didn't help.
1) SortedLIst has a GetKey property: you ask for the nth key in the sorted list of keys and you get it. SortedList(of TKey, TValue) does not have this kind of feature. Why not?
2) SortedList stores values as "object." Is this a less memory-effective method to store values of Double than SortedList(of TKey, TValue)?
In My Code i am using Dictionary(Of String , String) As Key Value Pair ..While i am using LINQ to Query this Dictionary, It Shows Dictionary is not Queryable.
View 1 RepliesThis should be extremely simple but I'm still new to the language and don't grasp the basics yet.
[Code]...
I need a simple LINQ query on VB.NET on the dictionary [Code] What I need here is to retrieve a SINGLE website (dictionary value of string type) or NOTHING (if the query cannot find an affordable result) given those rules: The dictionary key (integer) must be greater than startSite and not equal to mainSite or returnSite (both must be excluded from the result) Any hint? [Code]
View 2 RepliesI created my own Dictionary class, based on the .NET Dictionary. Now I want to overload then Item() Method. This works fine with the following code: Public Overloads Property Item(ByVal key As TKey) As TValue
[Code]...
I am writing a class library to interact with a domain Active Directory. In my object model, I have the following:
Domain;
Organizational Unit;
Group;
User.
In my Domain object, I have an Entries property and an Add() method.
public class Domain {
// The ReadOnlyDictionary<TKey, TValue> is a custom wrapper over an IDictionary.
public ReadOnlyDictionary<string, IDirectoryEntry> Entries { get; }
public void Add(IDirectoryEntry entry) {
Entries.Add(entry.Name, entry);
[Code] .....
For your information, I implemented the INotifyPropertyChanged interface to ease my life, but I don't seem to find a way to make it work the way I want. Perhaps am I not doing things right somehow, as for the location of different methods, I don't know. How can I make my Domain aware of a change that occured within one of its Entries, so that the TKey value is also changed? That is wanted because one could possibly add an entry, change its name meanwhile adding a new entry with the "old" name of the actual within entry, and cause a conflict, etc. In the end, causing the test to fail. But I'd like to make it pass like it actually is. Is there another better approach or workaround?
I would like to implement a generic Linq query on a DataGridView.DataSource to retreive a row whith an idField. I did search MSDN, StackOverflow, etc... but didn't quite find what I'm looking for. how I could implement it ?
This is the non-generic code, but I would like to make it work whatever the type of the DataSource is (as long as it implements IEnumerable I guess) and the name and type of the key field.
Dim query = (From note In notesList _
Where note.IdNote = mIdNoteSelectionne _
Select note).FirstOrDefault()
Dim ancienIndex As Integer = notesList.IndexOf(query)
noteList is a List(Of Note), Note is a simple entity class I created, with just members and properties
This is in VB, but feel free to send some C# code, I'll translate it.
i need to query the datatable & set the outcome as datagridview controls datasource
vb.net
Private Sub Txt_Search_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Txt_Search.TextChanged
'routine objective:- Filter datatable & set the datagridview datasource
[code]....
user.fld_usr_name is a string with the value random name user is an object that is given as a parameter
ByVal user As GUser
this is the linq query that doesn't work
Dim result = (From usr In users Where usr.Name.Contains(user.fld_usr_name) Select usr).ToList()
this is the one that works
Dim result = (From usr In users Where usr.Name.Contains("random name") Select usr).ToList()
this is the error
Object reference not set to an instance of an object.
I am using this in Linq to Active Directory library which probably means it's linq to entities I've tried everything?
I want to group items from a linq query under a header, so that for each header I have a list of objects that match the header title. I assumed the solution would be to use ToDictionary to convert the objects, but this allows only one object per "group" (or dictionary key). I assumed I could create the dictionary of type (String, List Of()), but I can't figure out how to write it. As an example I have written a simplified version below.
[Code]...
The below query fails with Null Reference Exception when there are elements in BOMIDs where MatID property is nothing.I thought the 'x.MatID isnot Nothing AndAlso' would prevent the x.MatID.Process part of the where from being executed. There are a couple elements in the BOMIDs collection that where MatID is nothing.
From x In BOMIDs _
Group Join y As PurchasedProcess In SpecialProcesses _
On x.MatID.PurchasedProcess Equals y.Name _
Into G = Group _
[code]....
I have the following object:
countDictionary As Dictionary(of Category, Dictionary(of Date, Integer))
The Class has a Enumeration Property. For the purposes of demonstration, I'll call it MasterCategory.I have been trying to get out an object that looks like the following:
groupedCountDictionary As Dictionary(of MasterCategory, Dictionary(of Date, Integer)
The best result I could get was:
Lookup(of MasterCategory, Dictionary(of Date, Integer))
From:
countDictionary.ToLookup(Function(o) o.Key.MasterCategory, Function(o) o.Value)
Which results in a IEnumerable (Of Dictionary(of Date, Integer)) for each MasterCategory value.However, I need that IEnumerable of Dictionary flattened to one dictionary with all the integers summed (total counts) for each date. I then tried to use various selects and group bys (from numerous stackoverflow posts) to "flatten" it, but my efforts have fallen short.
Current Code
[Category Class]
- MasterCategory As Enum
- Name As String etc
[code]....
I have created a Dictionary class (MyDictionary for the example). I am currently trying to pass MyDictionary into a function, filter it into a new instance of MyDictionary and pass this new instance into another method. When I am attempting to create the second instance from the filtered first instance of MyDictionary via Lambda Expressions and the ToDictionary Method, I am getting the following error:
Unable to cast object of type 'System.Collections.Generic.Dictionary`2[System.Int32,System.String]' to type 'MyDictionary'. I have simplified the example and recreated it in LINQPad and am getting the same error.
Here's the simplified version of my code:
[Code]...
I know that LINQ queries are deferred and only executed when the query is enumerated, but I'm having trouble figuring out exactly when that happens.Certainly in a For Each loop, the query would be enumerated.What's the rule of thumb to follow? I don't want to accidentally enumerate over my query twice if it's a huge result.
For example, does System.Linq.Enumerable.First enumerate over the whole query? I ask for performance reasons. I want to pass a LINQ result set to an ASP.NET MVC view, and I also want to pass the First element separately. Enumerating over the results twice would be painful.It would be great to turn on some kind of flag that alerts me each time a LINQ query is enumerated. That way I could catch scenarios when I accidentally enumerate twice.
I'm trying to sort a dictionary by value with LINQ but I can't figure how the ToDictionary() method works.
All the examples I can find are in c#.
here's my code
Dim f As Dictionary(Of String, String) = (From value In projectDescriptions.Values
Order By value Ascending
Select value).ToDictionary(???)
[Code].....
As I am beginner in LINQ, I have small problems. I have dictionary of Char and Long, and I would like to use LINQ to retrieve Char with highest Long Value. I saw some C# samples, which look pretty easy, but I can't achieve such expression in VB.Here are two expressions, and I don't think they are most efficient possible.
[Code]...
I have a dictionary collection as bleow:
mydic.addvalue(key1, val1)
mydic.addvalue(key2, val1)
mydic.addvalue(key3, val1)
mydic.addvalue(key4, val2)
mydic.addvalue(key5, val2)
From the above dictionary I want to delete all the entries where value == "val1", so that the result would have only following entry:
mydic.addvalue(key4, val2)
mydic.addvalue(key5, val2)
My VB source code is on VS2008 and targeted for 3.5
I have a Dictinary(Of String, Item) and I'm trying to sort it into alphabetical order by the item name. I don't want to use a sorted dictinary and without it, I've having zero luck. Linq is not my strong point.
[Code]...
How to avoid for loop (Dictionary Array) using LINQ
View 1 RepliesI've got a Dictionary(Of SomeEnum, Integer) that gets filled up while looping through some objects that have a property with type SomeEnum. Once the loop is done, I want the SomeEnum type that occurs the most in the list of objects. I also need the other counts as well for display purposes, hence the usage of a simple Dictionary(Of K, V).I am looking for a LINQ query to give me back the SomeEnum key that occurs the most by looking at each keys number of occurences. Or perhaps there's an easier way of going about it.I could do this:
Return (From kvp As KeyValuePair(Of SomeEnum, Integer) _
In Me.MyObjects Order By kvp.Value Descending _
Select kvp).First().Key
But wouldn't the sorting be a more expensive operation than trying to wiggle Max() in there somehow?
I have spend a couple of hours trying to figure out why my generic Dictionary(Of String, String) is not ignoring case.Here is my code:
Dim test As New System.Collections.Generic.Dictionary(Of String, String)(System.StringComparison.OrdinalIgnoreCase)
test.Add("FROG", "1")
[code].....
given this function:
Public Function Search(ByVal StartIndex As Integer, _
ByVal MaxResults As Integer, _
ByVal AccountNumber As String, _
ByVal LastName As String, _
[Code]....
instead of what I expected:
Select count(*) from remitline where lastname = "smith"
What am I doing wrong building up the where clause? I'm using Castle ActiveRecord 2.1
if there is that much of a performance gain in running a LINQ stored procedure versus a LINQ query?
View 1 RepliesI have a collection as follows
Private _bankRates As Dictionary(Of RateSourceBank.Key, RateSourceBank)
Where RateSourceBank.Key is simply
Public Class Key
Public RateType As String
Public EffectiveDate As DateTime
[Code].....
I have to join two main tables, and I need to filter the results by elements in an ASP.NET web form. These filters are created on the fly so I have to use a lot of where extensions to filter the query. I want to execute the query with as optimized SQL as possible.
I am first doing a simple join between TW_Sites and TW_Investigators. Then there are two sub-tables that are involved. TW_InvestigatorToArea and TW_InvestigatorToDisease. While most of the where clauses are working fine, I have found a performance issue that won't be an issue right now, but will be an issue as the table gets bigger.
The arrays DiseaseCategories and DiseaseAreas would be the results of a CheckBoxList result.
Protected Sub LoadResults()
'Get Dictionary of Filters
Dim FilterDictionary As OrderedDictionary = Session.Item("InvestigatorFilterDictionary")
' Initialize LinqToSql
[code]....
I'm trying to use reflection with LINQ on a sub that set datasource of all my ComboBox:
Usual Method:
' ACAmp Panel
cboACPanelAmp.ValueMember = "IDACAmp"
cboACPanelAmp.DisplayMember = "Description"
cboACPanelAmp.DataSource = m_Entities.ACAmps.OrderBy(Function(c As ACAmp) c.SortOrder).ToList
Want to use that sub
FillCbo(cboACPanelAmp, "ACAmp")
Private Sub FillCbo(ByVal cbo As Infragistics.Win.UltraWinEditors.UltraComboEditor, ByVal entityName As String)
cbo.ValueMember = "ID" & entityName
[code]....
I can't figure out the last part of the last line, the LINQ
