Iterate Through The Keys And Values Collections Of A Dictionary Object Using An Index?
Apr 25, 2009
I have a VB.NET project where I am able to iterate through the keys and values collections of a dictionary object using an index:
MyDictionary.Keys(idx)
MyDictionary.Values(idx)
When this code is taken from the test project and placed into the real project I get the following error:
'System.Collections.Generic.Dictionary(Of Double, String).KeyCollection' cannot be indexed because it has no default property.[code]...
In the line in sub search that says "dtf.Keys(idx) = 0" place your cursor after the right parenthesis and backspace you should get a tooltip that says, "<Extension> ElementAtOrDefault(index as Integer) as Double - index: the zero based element of the index to retrieve.
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Jul 7, 2010
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]...
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Sep 22, 2010
Very easy today, I think. In C#, its:
Dictionary<String, String> dict = new Dictionary<string, string>() { { "", "" } };
But in vb, the following doesn't work.
Public dict As Dictionary(Of String, String) = New Dictionary(Of String, String) (("",""))
I'm pretty sure there's a way to add them at declaration, but I'm not sure how. And yes, I want to add them at declaration, not any other time. :)
I've also tried:
Public dict As Dictionary(Of String, String) = New Dictionary(Of String, String) ({"",""})
And...
Public dict As Dictionary(Of String, String) = New Dictionary(Of String, String) {("","")}
And...
Public dict As Dictionary(Of String, String) = New Dictionary(Of String, String) {{"",""}}
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Sep 1, 2009
I'm trying to create an export Excel/CSV function that will iterate through a custom object and first output the property names and then output the values. I want to use reflection only where necessary so I'm attempting to save the property names when I output the headers and then reuse them to print the values. Is this possible? I'm a little weary of using reflection in a loop but is there a better way?
[Code]...
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Mar 11, 2011
I have a dictionary of type:
Dim parentDictionary As Dictionary(int,Dictionary(string,string)).
Dim childDictionary As Dictionary(string,string).
parentDictionary.Add(1,childDictionary)
Now I need to iterate over childDictionary to fetch key value pairs.My childDictionary is inside parentDictionary.
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May 20, 2011
If i wish to put items into a System.Collections.Generic.Dictionary, I can either Add or set the Item.I know if you do Add it helps you check if the key already exists and if not it throws an exception.Now I'm curious, so if I'm adding a ton of items, should I prefer setting Item instead of Add since Add does unnecessary checks that may actually slow things down?
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Jan 25, 2010
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]...
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Apr 16, 2012
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]....
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Oct 29, 2009
Public extreme_foods As New System.Collections.ArrayList()
[Code]...
anyone know why extreme_foods(i)=s is giving INDEX OUT OF RANGE??
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May 31, 2011
I have a dictionary(of someType, someOtherType) (the types are immaterial). With a given value, I need to find all the keys that have that value in the dictionary. What I am currently doing is this:
Dim foundList as New List(of someType)
For each key as someType in myDictionary.Keys
If myDictionary(key) = givenValue Then
[code]....
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Dec 15, 2011
I'd like to have something like:
[Code]...
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Nov 10, 2010
I have the following dictionary:
Dim idQueuedJobs As IDictionary(Of Int32, KeyValuePair(Of String, Int32)) = New Dictionary(Of Int32, KeyValuePair(Of String, Int32))
Why duplicate KeyValue pair? This is because the first Int32 is just a normal index, and the String followed by another Int32 contains systemnames and the priority of the qued job in idQueuedJobs
I want to calculate the total number of systemnames in idQueuedJobs, how can i obtain this count by using the groupby method?
Something like this maybe?
numberOfSystems As Int32 = idQueuedJobs.Values.GroupBy(...)
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Aug 3, 2009
I have this dictionary..
Dim Rooms As New Dictionary(Of Integer, Of Integer)
Rooms(1) = 101, 102, 109, 110
Rooms(2) = 103, 104, 105
Rooms(3) = 106, 107
I want to know if i can obtain how many keys are in the dictionary For example, in this dictionary i have 3 keys, and if i use Rooms.Count it returns me 9 thats each pair of keys-values, but i want to obtain 3, each diferent value as key.
EDIT: Sintax error P.D: I cant use now because i have to use in a webservice filtered by IP, but VS2010 if i use count on the dictionary, tells me that will contain the number of the keys/value pairs.
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Jun 9, 2012
I have this dictionary..
Dim Rooms As New Dictionary(Of Integer, Of Integer)
Rooms(1) = 101, 102, 109, 110
Rooms(2) = 103, 104, 105
Rooms(3) = 106, 107
I want to know if I can obtain how many keys are in the dictionary. For example, in this dictionary i have 3 keys, and if I use Rooms.Count it returns me 9 that's each pair of keys-values, but I want to obtain 3, each different value as key. Syntax error. I cant use now because I have to use in a webservice filtered by IP, but VS2010 if I use count on the dictionary, tells me that will contain the number of the keys/value pairs.
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Oct 7, 2010
I have a dictionary with the keys being integer and the values being string. I was wondering how can I sort the dictionary in DESCENDING order using its keys.
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Jun 4, 2011
how can i manually iterate through an entire datatable record by record, but only moving to next record after clicking a button. am using vb 2008 express and below is the code i wrote: Private Sub STARTButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles STARTButton.Click
Dim RealName As String
Dim UserName As String
Dim PASSWORD As String
[code].....
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May 31, 2012
I have a case insensitive dictionary in asp.net/vb.net like this:
Dim caseInsensitiveDictionary = New Dictionary(Of String, Single)(StringComparer.OrdinalIgnoreCase)
it holds values like this
[code].....
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Apr 2, 2010
Is there any reason to favor one of these approaches over the other when inserting into a generic dictionary with the possibility of a key conflict? I'm building an in-memory version of a static collection so in the case of a conflict it doesn't matter whether the old or new value is used.
If Not mySettings.ContainsKey(key) Then
mySettings.Add(key, Value)
End If
[code].....
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Dec 5, 2010
I am trying to find a record within a nested Dictionary, so that I can add more records to the sub-Dictionary.
The intention is to be a dynamic configuration, where no matter what I pass into it will group into like item categories that have already been added. If there are no like items it will add a new category.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim xConfig As New Dictionary(Of String, Dictionary(Of Int64, Object))
[Code].....
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Dec 17, 2010
How can I get the key of a dictionary by passing the index value? I'm trying: If rs.Fields("NM").Value = dictNM.key(0) that is, I want it to compare to the first key in the dictionary but I get the error Compile error: Invalid use of property I tried googling, but to no avail. I'm hoping this is even possible.
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Jun 15, 2011
Is it possible to retrieve the index number of an item/key in a Dictionary(Of TKey, TValue) object?
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Nov 18, 2009
I have a generic dictonary which is templated in the following manner:
[code...]
If I wanted to omit certain list items against arbitrary keys (that is the items that are in the list contained within the value part of each of the key value pairs making up the dictionary) given some arbitrary condition (lets say omitting list items where a list item contained the string "abc")
I would expect to able to create/project into a new dictionary which would contain entries which contained lists WITHOUT those items whose name contained "abc"
How do I achieve this using a Lambda expression?
I was trying something like this:
[code..]
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Sep 8, 2011
I'm trying to setup a WCF web service to be consumed by JavaScript using JSON and jQuery.I've noticed that you can send JSON without a DataContract if the service method parameters match the naming structure of the JSON object:
<ServiceContract(Namespace:="http://foo.com/bar")>
<AspNetCompatibilityRequirements(RequirementsMode:=AspNetCompatibilityRequirementsMode.Allowed)>
[code]....
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Mar 23, 2011
I'm debuging an complex calculation object in my project, and I'd like to show its various and many properties in a textbox, to make my tests easier.
Can I do something like
for each p as someKindOfProperty in MyObject1
debug.print(p.name & " - " & debug.print p.value)
textbox1.text = textbox1.text & vbcrlf & p.name & " - " & p.value
next
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Jan 31, 2012
I have a dictionary that I want to access with a key that is the combination of a string (AcctNum) and a date (BalDate).It seems to me the simplest approach is to create the key by simply converting the date to a string and concatenating:MyKey = BalDate.ToString & "|" & AcctNum
I know I also have the option of creating a composite key by writing a separate class and overriding GetHashCode() and Equals() a la this solution. To me, the concatenated string is a simpler, if somewhat less elegant, solution. Am I missing some compelling reason why I should go with the composite key class approach?
This lookup is the crux of the project I am working on, so performance is my main objective (with readability a close second).
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Jun 12, 2012
Am using a combo box with no of phone numbers .I want to get the phone no one by one in a variable. Now am using the below code to get the combobox values. But still now am getting the following error message System.Data.DataRowView. Please help me to fix this error. am new for vb.net.[code]
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May 14, 2011
I'm building a litle console app that involves a control hierarchy -- there are screens, and inside of screens you can compose controls together.
You can add controls to a screen by declaring member variables (which all inherit from AresControl). The control constructor takes a simple coordinate pair. It looks like this:
Public Class IntroScreen : Inherits AresScreen
'Controls
Private LabelSelect As New LabelControl(72, 0)
[Code]....
This would result in cleaner, convention-based code. But try as I might, I can't get it to work - I can walk the member variables of a type, but I need to walk the member variables of a live object.
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May 9, 2010
I am trying to match the values of a combo box which are typed inside a combo box with the comb box items, which are bind to a datasource. i can see the items in the combo box and if i get the selecteditem its working fine means nothing is wrong with the connection and other things. but when im trying to match the values im getting this error:System.Data.DataRowView and this error continues to display equal to the number of rows inside table. im using the following code:
[Code]...
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Feb 21, 2012
How can I iterate through a listview that has checkedboxes and get the value of the first column? The listview has 3 columns, "ID" "Survey" "County". I want to get the value of the "ID" column for the items that are checked. I've been using the following code, but can't figure out how to proceed. am I on the right track?
[Code]...
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Jul 30, 2009
I have an class named Foo. This class contains a collection of child objects of type FooChildBase, but I also have a further class of type FooChildTwo which inherits from FooChildBase.
Class Foo
Public Children As IList(Of FooChildBase)
End Class
Class FooChildBase
[code]....
What I would like to do is have my FooSpecial Class treat it's Children collection as if they were FooChildSpecial objects, but still be able to add FooChildTwo objects to it. Is this possible and if so how can it be done?
EDIT:I need to FooChildSpecial class to wrap any of the objects in the Children collection with the extra values, whether they are FooChildBase or FooChildTwo?
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