[URL]..But I can't design a solution. Could anyone try to help me out here? I know there are some workarounds to be found, but either the links are dead (check above link) or it's writter in a language I still can't read. Here's my code.
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I am coding a VB.NET application which heavily deals with a collection type. See the code below:
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I have to type the above line for so many times. If I changed the collection type, then I have to make the change for all the instances. So if there is a way to use "a typedef equivalent", then I can get rid of all these problems. I tried with imports, but it is only for namespaces and it can't be used for classes.
Note: I am using VB 2008, windows XP. The application type is windows forms(VB). EDIT: I made some tries based on code_gray's below answer. This is the first try.
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I have a legacy COM-component with an interface declaring a property like this (IDL notation):
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This interface is implemented in a calling application written in VB6 like this:
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Everyting works fine until I try to do the same in VB.Net. VB.Net refuses to compile code where a parameter of a property is passed ByRef. MSDN says VB.Net doesn't allow such parameters. Is there any way I could implement such a property in VB.Net?
I'm trying to integrate with an API that requires the "Date" header in a web request. As you may well know, .NET has removed the ability to append or even display a default Date header in your request, so I was wondering about a workaround.Here's the catch: you can't use TCPClients because I don't have "permissions" on my server for such a thing as sockets. Is there some way to "cheat" the system to fake a date header or to trick it into posting a Date header? Or should I just give up on this API?
View 3 Repliesthere any workaround with this one?
SELECT invoices.no, customers.name, invoices.mdcode,
SUM(iproducts.unitprice * iproducts.quantity) AS total,
SUM(iproducts.unitprice * iproducts.quantity) - SUM(rinvoices.payment + rinvoices.discount)
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I know CodeDom doesn't support partial methods, but is there a workaround? I found a workaround for C#, but I need one for VB.NET.
View 2 RepliesI know that there is no DESIGN, DESIGN_MODE, DESIGN_TIME, etc preprocessor directive value. However, I need something that can do the trick. I can't use a normal If statement, because in my case I need to change the inherited class so that the control renders properly at design time. If not, I'll receive an exception due to the fact that the inherited class is an abstract class.Here's what I'm looking to accomplish:
Partial Class MyCustomControl
#If DesignMode Then
Inherits UserControl
#Else
Inherits WidgetControl
#End If
I'm downloading a bunch of files from a URI but when they get big, I get an utOfMemoryException. I thought at first it was MemoryStream error but I'm pretty sure now that the error is rooted in the declaration of an array of Bytes that's too large. (Half a gig is fine, 1.7 gig is not.)
View 1 Replieswhat's a Class, and Object, a Method, a property and thins like that, but I have this doubt:Let's supppose I have a class "Laundry" this class has (just for this example) 3 propierties:
1.- laundryID
2.- Name
3.- Washers
Id and Name are "primitive" types or simple types (integer and string), but Washers, represent a list of object of type "Washer", that has 3 properties:
1.- washerID
2.- laundryID
3.- capacity
4.- brand
All of them (for this example) simple/primitives types (integer,string,string).So this my dilemma, it is correct to have a constructor like this (VB .net)
public sub new(ByVal laundryID as integer)
'' Here I'll query for the data of the Laundry on DB
'' After that I will query for every washer that belongs to this laundry
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And inside of that constructor query for all the washers that belongs to the laundry with id=laundryID parameter, and create objects of type "Washer" and add them to the list of Laundry ?I'm not sure If I explain myself, any comment I'll be really grateful, in less words, what's the correct approach (or good practices) to work with class/objects that has properties which are complex (other class/objects).I usually work with ADO.net probably ADO/LINQ/Entity solve this thins in an transparent way, but if they do it I don't really know it.
Note: I'm familiar with VB.net, C#, PHP, so if you prefer explain/help me using examples with its syntax, it's ok
It's kinda overkill (i7, 8GB, SDD, W7 x64) for what I actually need but it is supposed to last for a few years.For maintenance issues I had to install Visual Studio 2005 and it turns out that "Edit and Continue" wasn't working . I found a thread here HTML Code:[URL] in which I read that E&C is not supported in 64-bit OS.
View 2 RepliesI'm trying to make a label transparent. When I set the BackColor to transparent, all it does it take the color of the form it's sitting on, i.e. It's not truly transparent. I've googled it and found this in another thread (from a MSFT MVP)".NET controls do not support true transparency. You can set their BackColor to Transparent (in some but not all cases) and the parent control will show through, but only the parent control. If there is some other control behind that is not the parent it will not show through. That's because the control is not truly transparent. It basically copies its parent in the area behind it and uses that as its background, but that doesn't include sibling controls that may be behind it as well." To me, this is completely unacceptable. Why even include the transparency option when all it does is set the control's backcolor to the form color? I'm trying to add a label over a progress bar to give my user some feedback (because the Visual Studio progress bar doesn't support text, which is also a horrible design shortfall by the way), and have yet to find a way around this.
View 6 RepliesI found using AndAlso/OrElse, all the time, VERY annoying. It reduces code readability, especially when conditioning get complicated.
View 2 RepliesUsing VS2010 and VS2008
I have a DataGridView bound to a DataTable which has an Int16 DataColumn. The DGV has a DataGridViewComboBoxColumn tied to the DataColumn.
I enter integer values in the Items section of the DGVCBColumn properties. When I run the program I get "DataGridViewComboBoxCell value is not valid".
I assume this is because my Items are text and the data column is integer so I created a List of Integer, added my integer values/choices to the list and made the List my data source for the ComboBox column. Same error.
I then created another DT in the DS with one column type Int16, added my integer choices to the DT, created a BS for the ChoicesDT and set this BS as the DataSource, the column as the DisplayMember and the ValueMember. Same error.
There are no issues like this when the DataColumn is bound to a ComboBox outside of the DGV so I assume there is some issue with the DGV understanding the underlying binding.
I have a datagridview and a column which is DataGridViewComboBoxCell
I want to set datasource for that DataGridViewComboBoxCell?
The problem I have now is that I can not get the value selected as a combobox, I'm trying to set the text and value to each item in the combobox of each cell in the datagrid.
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On a form I have a DataGridView. Inside this DataGridView i have several columns of which one is combobox and the others are textboxes.The combobox column is populated with values from a MySql database table using a query. So far so good. What i want next is to populate a certain textbox from that DataGridView, automatically after a value from the combobox is selected. When a value is selected from the dropdown list of the combobox, that value is used in a SQL query to find the value that will be displayed in the textbox.All the textboxes and the combobox are inside the DataGridView!)I did this using DataGridView EditingControlShowing event because a DataGridViewComboBoxCell does not have aSelectedIndexChanged event.The value is displayed correctly in the textbox, but the problem is that the value selected from the combobox disappears after the selection, and the combobox remains empty. I need the value to remain in the combobox after it was selected and after the corresponding value was inserted in the textbox!Here is the code for this:
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Private Sub test_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Populating the combobox
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I have come accross many scenarios of handling datagridviewcombobox events, however none seem to fit my scenario, or I may be missing something.1. I need to capture the column index that the combobox is resident in. This is because I have a complete row of comboboxes that should set the header text to the selected value.here is the code I have so far:' I also use a list of string as datasource publicly declared
Public cs As New List(Of String)
'to insert the combo's into the grid
Dim row As New DataGridViewRow
cs.add("Book")
cd.Add("Author")
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I get the following error message when entering edit mode on a DataGridViewComboBoxCell:
System.NullReferenceException was unhandled Message=Object reference not set to an instance of an object.
Source=System.Windows.Forms
StackTrace:
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I have a DataGridView with two DataGridViewComboBoxColumns. I want to use the selected item in the first column to trigger a re-population of the items in the second column, on a per-row basis.
Here's the code I have so far. "addlInfoParentCat" identifies the first column, and currentRow.Cells.Item(1) is the DataGridViewComboBoxCell that I want to re-populate. ExtEventAdditionalInfoType is a type I defined that contains the string/value pairs.
Private Sub dgvAdditionalInfo_CellValueChanged(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles dgvAdditionalInfo.CellValueChanged
Dim currentCell As DataGridViewCell
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I want to have a DataGridView that has two columns.The first column will always be of type DataGridViewComboBoxColumn. Based on the selection in that column, I'd like to be able to change the corresponding cell in the second column to either a DataGridViewComboBoxCell or a DataGridViewTextBoxCell.I'm thinking I just need to make the second column of type DataGridViewColumn, but don't understand the mechanics of how to change the cell type on the fly.I'm working with VB.NET in Visual Studio 2005.
Update: One way around it, I suppose, is to make the second column as a DataGridViewComboBoxColumn, and change the attributes of the cell so that it either behaves like a drop-down list, or as an (editable) drop-down with no elements. The latter looks enough like a text box that I could live with it, and it wouldn't involve changing the type of the cell.
I'm getting some data from a database and I'm setting them to a DataGridViewComboBoxCell. I also need to set the Tag property of each DataGridView ComboBoxCell item to a specific value, so later, I can query the DB with those two items.The issue, is that I can't seem to figure out how to access the DataGridViewComboBoxCell Item's Tag property.[code]I wrote it on the spot and it wasn't until later that I realized that I'm setting the Tag property of the DataGridViewComboBoxCell itself and not the DataGridViewComboBoxCell's Items.
View 7 RepliesHow do I set SelectedIndex of a DataGridViewComboBoxCell?The code fill the combobox with items, but I need to select one of them My Code:
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DataGridViewComboBoxCell Tag cleared in EditingControlShowing event?
View 2 RepliesI have a TextBox column in my DataGridView. When the user clicks one of the cells in the column I turn that cell into a DataGridViewComboBoxCell and fill the items using the columns Tag property which is a 1-dimensional array with 3 items. This is what my Tag looks like:
?CType(sender, DataGridView).Columns(e.ColumnIndex).Tag
{System.Array}
(0): ""
(1): "No Reportable Result"
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I am using VB 2010 Express to create a windows forms application with an unbound DataGridView. The DataGridView has multible columns, two of which are ComboBox Columns. I would like to make the borders of the cells be bold when selected as some type of indication to which cell is the current cell. It is possible that I overlooked something completly but I could not seem to find a property that would allow this to happen.
My solution was to create a custom class which inherits from the appropriate DataGridViewCell type (e.g. DataGridViewTextBoxCell, etc..), in that class I override the Paint sub. There I check the selected property and draw a rectangle using the cell bounds.
This works with every type except the DataGridViewComboBoxCell. On the columns of this type I receive an ArgumentException on the call to the Paint Sub. Even if I just have an empty class that only inherits from the DataGridViewComboBoxCell.
Again, it is quite possible that I have overlooked somthing and am making the a lot more complicated than it needs to be.
i encountered a problem but this happened on the client side. In my PC, i don't encounter this error.
The error is: System.argument datagridviewcomboboxcell value is invalid
Is there anyone who encountered this problem? Could the client's PC needs updating on a certain dot net fix?
I have an error but will explain how i set up my db:Two tables, One is called Area and the other Postal_Code.
The aim is to assign a postal code to the area.Sometimes we add postal codes and sometimes these codes change or need to be deleted.I used the wizard to create the datasets and dropped them on two forms linked to a SQL db.We can Add,Edit,Update & Delete so all is working fine there is no relationship between te tables as they dont need to be linked, I only require the PCode to me added to the Area Table, not any ID or Index etc.
One of the fileds in the Grid on the Areas form is the Postal Code, its set to a combobox that when the user is adding it gives them a selection of postal codes to select from.I get the error when loading the datagrid on the Area form: System.ArgumentException: DatagridViewComboBoxCell value is not valid
This happens only when the postal codes are changed or deleted in the Postal codes table.
I know what causes the error - the dropdown on my Areas form looks for the value in the Postal Code table and does not find it beacause it has either been changed or deleted.Im doing this manually - I go into SQL and remove the postal code data from the record.Then the form loads with no errors.
Q: Is there any way when the Datagridview loads that I can tell it when the PCode does not exsist in the Postal Codes table that it should rather leave it blank and warn the user that there are errors they need to fix befor they can save.
Given a datagridview, using complex binding I have a datagridviewcomboboxcolumn that displays data from a different table. My question is: when the dropdown list of the comboboxcell is shown is it possible to display a different text than the DisplayMember, lets say more detailed?I search for a solution but could not find any.
View 3 RepliesI have a DataGridViewComboBoxColumn, and want to switch the style of the ComboBox control between DropDownList and DropDown (mainly for the text field editing capability). I'd like to do this on a row-by-row basis (at the DataGridViewComboBoxCell level).How would I do that programatically? Or maybe a different way of asking: How do I access the ComboBox control given an object of type DataGridViewComboBoxCell?
View 1 RepliesI've tried pretty much everything to solve this problem (except what works, obviously) and almost worn out Google, so now I'm giving this forum a chance. Basically I'm making an application which needs to map column names in an excel spreadsheet to fields in a table (TableB) through a data transfer setup table(TableA); To make this work as planned, I need to compare a value in "FromField" in TableA with headers/column names read from an excel spreadsheet into a list of strings, and if they match, map "FromField" against "ToField", prior to importing data from the spreadsheet. The column names that don't match with "FromField" are to populate a combo box in the FromField column in my DataGridView.
PROBLEM: I get this to work fine as long as I don't handle case differences (e.g. "FieldToBeImported" in Field1 vs. "fieldtobeimported" as header in spreadsheet), but this prevents matching words with case differences to be mapped, and leaves it to the user to manually map fields that should have been mapped automatically. However, if I make a ToUPPER copy of the List Of String that contains the MS Excel column names and compare them to a ToUpper version "FromField" data, I get the error message from the topic:
"System.ArgumentException: DataGridViewComboBoxCell value is not valid"A little explanation on DataGridView2 before diving into the code: Column in index 0 is a DataGridViewComboBoxColumn added in code, where matching fields in column 0 and 1 are mapped, and non-matching fields are populated in the combobox.Column in index 1 is "ToField" (TableA as source), Column in index 2 is "FromField" (TableA as source) and is hidden in runtime.
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