How do I Display A HashSet As Either A Collection or an Array in the PropertyGrid.I wish there was some Attribute that allow me to display IEnumerable as an Array...but so far my attempts to do that have failed!My current solution is unacceptable in the new places I want to use it in
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I have an object with a property that is a collection. When I point the PropertyGrid to the object it displays the ellipses for the collection. When I click it I get the generic collectioneditor. Of course the Add put fails because my collection is strongly typed. I need an example of how to create a collectioneditor that will create my collection's objects.
View 4 RepliesI'm using a PropertyGrid to display properties of my custom object, but whenever I run the form and input stuff into the collection, it doesn't save... If I open up the CollectionEditor again, its blank.. heres my code
<Editor("System.Windows.Forms.Design.ListControlStringCollectionEditor, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", GetType(System.Drawing.Design.UITypeEditor)), MergableProperty(True),
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I would like to display static (shared) objects at runtime in a PropertyGrid but if I try to set the selected object property of the grid like this:
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Is there a way to display a static (shared) object or the object's properties in the PropertyGrid?
I know that the .Contains method on a hashset is fast. My question is what is the best method for getting the hashset data before repetitively using the .Contains method?
I can think of 2 options. Both of these examples would be called in a loop of undetermined length.
1) Call the method that returns the cached hashset directly and use the .Contains method.
IF (GetHashSetMethod.Contains("TESTVALUE") THEN BLAH, BLAH, BLAH...
2) Create a new hashset outside of the loop and load the cached hashset data into it so the method that returns the hashset is only called once, then use the .Contains method.
DIM HashTest AS HASHSET(OF String) = GetHashSetMethod
Then in loop:
if (HashTest.Contains("TESTVALUE") THEN BLAH, BLAH, BLAH...
I have been using method 1. Should I even think about switching to method 2? Is there a 3rd option I haven't even thought of? Does it even matter because the data is cached to begin with?
What are the differences between a HashSet(of T) and a list(of T). I recently discovered HashSet and it seems to be substantially faster and uses much less memory than a list, so why use a list at all ?
View 5 RepliesWould the following:
Dim stringlist As List(Of String)
Dim stringlisthas = stringlist.Contains("thing1")
be any slower than
Dim stringlist As List(Of String)
Dim stringlisthash As New HashSet(Of String)(stringlist)
Dim stringlisthas = stringlisthash.Contains("thing1")
Is a hashset needed for contains?
I created a custom class which just stores 3 byte values, (R G B to be exact), which constantly change. So my idea was to store that class in a HashSet, then create a new instance of the class (with different byte values) then add that to the HashSet. There can be duplicates, which is why I decided to use a HashSet, which will ignore an item if it's allready been added. Doing this on a List would be too slow.But I've ran into a problem. Adding a custom class to hashset seems to only allow 1 to be added. I assume this is because its hashing the class object while ignoring the data (byte rgb values) it contains? Is there a way around this? It's possible to convert the RGB to Color and just use that in the HashSet, but conversion is a bit too slow.
View 2 RepliesI am using an API where I'm constantly receiving collections of custom objects that I need to represent in some sort of grid. Almost universally I need to take the data in one of the columns and run another API call using it. For instance, the objects in the collection from the first call will have an ID string that I use to make another call to get the name. Here's an example collection:[URL]
I have tried two approaches to using a DataGridView:I've simply set the collection as the data source. If I remember correctly, that method wouldn't allow me to sort.I then created routines that would create a temporary datatable, create the columns I need, loop through each item in the collection adding it to the table, and then setting the datasource to equal the datatable.
This second method works for the most part but there are certain things I keep banging my head against. I am using the SelectionChanged event to load further details about the selected row into a panel below the DGV. When the datasource is set/changed this routine gets called a whole bunch of times and will fail because the various objects (ex. CurrentRow) I'm calling are null. When the DGV is sorted it gets called again and will fail for the same reasons. I can come up with kludges to avoid both but they are just that, kludges.
I am trying to generate random images from access database using hashset as it is said to be unique and there won't be any repeated images appearing. But, it doesn't seem to work. ow can i get it to work? By the way, i am very new to the concept of hashset.
Private Function GetImageFromByteArray(ByVal picData As Byte()) As Image
If picData Is Nothing Then
Return Nothing
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I am trying to generate random images from access database using hashset as it is said to be unique and there won't be any repeated images appearing. But, it doesn't seem to work.
How can i get it to work? By the way, i am very new to the concept of hashset.
Private Function GetImageFromByteArray(ByVal picData As Byte()) As Image
If picData Is Nothing Then
Return Nothing
End If
' is this is an embedded object?
Dim bmData As Integer = If((picData(0) = 21 AndAlso picData(1) = 28), 78, 0)
' load the picture
Dim img As Image = Nothing
Try
Dim ms As New MemoryStream(picData, bmData, picData.Length - bmData)
img = Image.FromStream(ms)
Catch
End Try
' return what we got
Return img
End Function
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Panel1.Visible = False
Panel2.Hide()
Dim conn As New OleDbConnection
Dim DA As OleDbDataAdapter
Dim DS As New DataSet
conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=db1.mdb;User Id=admin;Password=;"
DA = New OleDbDataAdapter("Select Empty, EmptyName, Target, TargetName from PicturesDisplayed", conn)
DA.Fill(DS)
Me.PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage
Dim oledbconnection As OleDbConnection
oledbconnection = New System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:Documents and SettingsAdministratorDesktopdb1.mdb;Jet OLEDB:System Database=system.mdw;")
oledbconnection.Open()
Dim command As OleDbCommand
command = New OleDbCommand("select count (*) from PicturesDisplayed", oledbconnection)
Dim count As Integer
count = command.ExecuteScalar()
oledbconnection.Close()
Dim randomImage As New HashSet(Of Integer)
' Create a integer and new Random object
Dim intPic As Integer
Dim rand As New Random
'Pick a random number between 0 and the number of images in database
intPic = rand.Next(0, count)
randomImage.Add(intPic)
PictureBox1.Height = 256
PictureBox1.Width = 256
PictureBox2.Height = 256
PictureBox2.Width = 256
Dim pic1x As Integer = _
(Me.ClientSize.Width - PictureBox1.Width) 2
Dim pic1y As Integer = _
(Me.ClientSize.Height - PictureBox1.Height) 2
PictureBox1.Location = New Point(pic1x, pic1y)
Dim pic2x As Integer = _
(Me.ClientSize.Width - PictureBox2.Width) 2
Dim pic2y As Integer = _
(Me.ClientSize.Height - PictureBox2.Height) 2
PictureBox2.Location = New Point(pic2x, pic2y)
' Now set the picturebox image equal to the image chosen from the array randomly using the random
PictureBox1.Image = GetImageFromByteArray(DS.Tables(0).Rows.Item(intPic).Item(0))
PictureBox1.Visible = True
PictureBox2.Image = GetImageFromByteArray(DS.Tables(0).Rows.Item(intPic).Item(2))
PictureBox2.Visible = False
If (randomImage.Count = count) Then
Me.Close()
End If
End Sub
I currently have the following bits of
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I want to add an array to the class `StopwatchStorage` but can't figure out how without some ambiguous warning or error popping up. The Array will contain TimeSpan type elements (essentually an array of Stopwatch.Elapsed values)
How do I declare and add a dynamically sized array to the class. I know that I will have to use the UBound function each time I want to add a new array.
I have 5 pictureboxes on my form and would like to but then in a collection or array to use them in a loop. I would like to use the FOR EACH loop... but how..
Th pictureboxes are placed in a Table. Here is my code so far.
Dim TableHeaders As String() = {"PERIOD", "GRADE", "SUBJECTS", "POSSIBLE ATTENDANCE", "ACTUAL ATTENDANCE", "% ATTENDANCE", "DISTICTIONS", "NUMBER ENROLLED", "STUDENTS WRITTEN", "STUD PASSED", "% RETAINING", "% PASSED", "TERM MARK", "NAT AVERAGE"}
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It says that PictureBox is a type and can not be used as an expression, so how do i do it?
Let say i have 10 properties of bindingsource.The names are: bindingsource1, bindingsource2, bindingsource3, ....., bindingsource10
i want to develop a code using loop for these properties.[code]...
Is it possible to replace the number in the bindingsource with i?[code]...
I am working with an XML web service using VB.NET, created using VS 2010. One of my web methods returns a collection(type that inherits from list) of custom objects. It's a simple return statement, it is my understanding that .NET handles most of the tricky protocol stuff as well as serializing/unserialzing of objects.
The issue is in my consuming application when I get the the return value of the web method that returns a custom collection I get an array of the custom objects. Is this normal behavior? It will be easy enough for me to take that array and insert it into a custom collection object but if I could I would like to skip this step.
Working on a project that tests up to 16 PC boards. The test routines are on a a backgroundworker thread. I want each PC board to perform the test routine on its own thread, so I would need up to 16 backgroundworkers.How do I go by doing this? Do I put 16 Backgroundworkers on the form? I tried to do it programmatically but I can't declare an array of backgroundworkers because withevents variables can't be typed as arrays. I guess I just need a kick in the right direction.
View 8 RepliesI have a group of boxes witch will all hold data input by the user. I am using an arraylist to store these, or atleast I am hoping to. So, the problem I have is getting the data to actually save to the arraylist. It keeps giving the error saying that type string cannot be converted to array list.
View 32 RepliesI have a collection which I wish to retrieve an array from in .NET 2.0. In other words, I want to convert a collection into an array. So far I have the following:
Public Class Set(Of T)
Implements IEnumerable(Of T)
Implements ICollection(Of T[code]....
I want to know how can I possibly copy a table with multiple columns and rows into an Array or Collection in VB.NET.I want to know the best solution because I want to use the code for 2 different tables and do some comparisons, and the second table has too many records.I was wondering if in VB.NET there is something similar to Hashmap used in java and a table could look like the following
View 1 RepliesI am using 2 dimensional arrays for my work. My problem working with them they are incredibly slow for my work. I am starting the array with randomly assigning values (non zero) to the array. Most of the array values are zeros as shown in below form (e.g. 5 x 5):
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I have a string array called m_DirFileList and a collection called myFileCollection. I'm trying to loop through the items in the collection and store each one in the string array. It's not working though.
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I have a string array called m_DirFileList and a collection called myFileCollection. I'm trying to loop through the items in the collection and store each one in the string arrayIt's not working though. This is what I'm trying to do:
Dim myFileCollection As Collection = clsFTPClientClass.GetFileList(fileFilter, True)
intItems = clsFTPClientClass.GetFileList(fileFilter, True).Count()
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I want to create a strongly typed multidimensional array or collection containing the following values from a database:[code]
View 3 RepliesI tried this
vb
Dim matches As String() = Regex.Matches(tmpFieldContent, strEmail).Cast(Of Match)().ToArray()
But it didn't work, as vb says
'Cast' is not a member of System.Text.RegularExpressions.MatchCollection'.
Is it possible to have a two-dimensional array/list/collection such as the following. The first dimension is to have 2 elements, 0 and 1. The second dimension I would like to be able to have a different number of elements for each of the elements in the first dimension. To explain better, I'd like X in array (0, X) to go up to say 4 and Y in array(1, Y) to only go up to say 2.
So there would be:
array(0,0)
array(0,1)
array(0,2)
array(0,3)
array(0,4)
array(1,0)
array(1,1)
array(1,2)
But no array(1,3) or array(1,4).
I'd also need to be able to use Redim Preserve to increase the size of the second dimension for each of the first dimension's elements.
I have a parameterized query that displays the info (name, phone number, email addy) in detailed text boxes vice a normal DGV. I have coded a button to open outlook and populate the email address, but what I would like to do is have the user click another button that would add each email address into an array or collection from the desired records. Then, when they added all desired recipients to this "collection" they would hit the email button, which would open up outlook with the To: box already populated.*
I have looked into dynamic arrays , generic and special collections but am not sure what the best way forward is. When using the dynamic arrays I didn't really get anywhere, I couldn't seem to figure out how to redim with each addition of an email address.
Dim emaillist() As String
Dim listings As Double
Dim addy As String
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I have to search within an array and display the number of occurrences that a value within the array appears. I know that my code is incorrect but this is what I have so far. If anyone can point out what I am doing wrong that would be great.
Private Sub btnResult_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnResult.Click
Dim intSearchAmount As Integer
Dim intCounter As Integer
Dim intIndex As Integer
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I'm having trouble with collections and how it works, what I have so far is classes and I have attempted to do collection but it is not working properly. I am trying to have the collection hold the classPerson,classCustomer, and classPreferredCustomer properties, and then display it to list and labels in the Main form. [Code]
View 7 RepliesI created a custom class for a custom object. I instantiate like so[code]...
Now, I have two problems. First, right now this is just overwriting the same object properties, again, and again. I need to somehow dynamically name the object. Then, I need to place these objects in an array so I can iterate through them...
I am working on my first VB application and have run into a problem. I am trying to loop through some data and displaying them in labels. I am using a for-each loop but end up with different row with the same labelname. What I would like to do, is to assign a number to the labelname (mylabel1, mylabel2,...), but I canīt figure out how, and I cant find anything online that will work. Here are some of the code that I have made, where I could use a solution to my problem...
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