I have over 9,00,000 records in my Access database but only a fraction of that is being displayed in the listbox. How Many Rows Can A Listbox Hold? Around 65K is the answer I got from my research.
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I have a form with a listbox bound to a tableadapter. Users can select from a combox, that has a list of users in it, then click "Add" to add it to the listbox and remove to remove it. This part works fine. The problem comes when updating the database:
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I want to delete Multiple rows of listbox, I tried this
For teller = 0 To 170 Step 1
ListBox1.Items.Remove(teller)
Next
But that doesn't work. How do I delete the first 170 rows in my listbox? :)
I have the following controls:
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I have a table on a MYSQL database called "messages" and a column called "message". When i type something into textbox1 and click button1 i want to add a row to "messages" under the column "message" with the title and message as its value.(separated by a hyphen, dash, or other small delimiter)Then reload listbox1's contents to show the new message. so i want the final message to be something like:
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I am working on Treeview control and Gridview Control VB.NET08. In the Treeview i have Parent and Child Nodes. Like:
- 31
3101
3102
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I am working on Treeview control and Gridview Control VB.NET08. In the Treeview i have Parent and Child Nodes. Like: [Code] Comparing the Parent Node text and first two digits in the Column values. I want to add rows inbetween the gridview rows based on the parent and Child Nodes. If i expand the First Parent Node Called "31" then according to the Number of Child Nodes (for first parent node(31) there are 5 child nodes.) add rows in the gridview.
These New rows should be add under the 31-xxxx. If i expand the 32 Parent Node based on number of Child Nodes, add rows under the 32-xxxx. [Code] I am getting the rows in the end of the Gridrow not in the Specific row.
How would i delete only the successful inserted rows for insert and then move the non successful rows up and allow the user to correct the data and get it ready for an insert. If i dont delete the successful rows then i will have multiple inserts of the same dataRow and we dont want that! AND if i dont move the data up then it will have blank rows uptop and will end the try and not insert the corrected data. You can better see what logic i am trying to perform at the bottom of my code, right after I insert into the database. Here is my code.
Private Sub btnLaserGenerateTicket_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLaserGenerateTicket.Click
'Function declarations
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when populating a data grid i keep getting a redundant row in the bottom. is there a way to lock grid rows to the number of rows in the data table?
View 1 RepliesI have three sub tables that I want to process. For each I want to combine the rows, as they are only different by contents in the second column(I want to do the same to the fourth column, later):
'Sub table 1
xx|C201 |02300877 |Samsung |....
xx|C201 |02300877 |Toshiba |....
xx|C213 |02300877 |Samsung
[code]....
p.s. For the fourth column, Manufacturer information , I want to do the same and I'd probably get something like this for the final table:
xx| C201,C213,C606,C619 |02300877 | Samsung
xx| C201,C213,C606,C619 |02300877 | Toshiba
xx| C303, C305,C712 |02301163
xx| C207, C209, C708 |02301165
I'm building a new industrial app using MODBUS/TCP talking to a DAQ unit that will have a lot of parameters and will need to be adaptable for different scenarios. For example, the units I'm connecting to have 12 inputs and 6 outputs, mapping for those may be different for each installation, and in one instance I'll be talking to 4 units together - if that's the best way to do it - each one will have identical parameters, just a different ID number and ip address. They will all be writing to a SQL Server database. Not sure if I'm better off having a Tab control with each unit on a separate tab or a different instance of the app for each one. Is one better than the other? The units will be polled every 200-500ms. 500ms seems to be more stable.
With so many parameters, is it better to store all them inside the application and access them through My.Settings or would I be better storing them in a database, either the SQL Server DB or maybe something like SQLite (one of my faves) or is there a better way?
Not done anything quite as big as this before and first time with MODBUS, but that bit is working a treat.
I am writing a program that is going to take two dates (entered by a user) and compare them against each other to determine when something was purchased vs when it was paid for. I'm ok with everything except one part, and its a biggie, how do I have the user enter the dates (format) and how do I convert it from a string to a recognized date format? Does that make sense?
View 4 RepliesCurrently, I use SendKeys.SendWait("{Left}")
How can I hold the left arrow down?
I really want to do this the proper way, it's just that I've been doing it the wrong way for so long, I can't seem to get past it.
in a console app if I start a timer or kick off a thread or bgw, the sub main runs right on thru and the app finishes and closes.
i need the sub main to just hold position until some event is raised then handle the event and come back to sub main or end depending if the event that was raised told us to end or not.
what I would normally use is this:
Do While KeepLooping
Wait(5D)
CheckTimedEvent()
Loop
So, if this is how to hold a key down for an infinite amount of time:
keybd_event(CByte(Keys.Right), CByte(MapVirtualKey(Keys.Right, 0)), 0, 0)
How can I hold it down for only 1 second?
I am currently using DevExpress 10.2 within Visual Studio 2010. In a previous question I was trying to print the current user view of a DevExpress GridControl with the user's choice of expanded or collapsed master rows and/or group sections. I was told this was not possible at this time. I have now decided to use the following code:
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How would i delete only the successful inserted rows for insert and then move the non successful rows up and allow the user to correct the data and get it ready for an insert. If i dont delete the successful rows then i will have multiple inserts of the same dataRow and we dont want that! :) AND if i dont move the data up then it will have blank rows uptop and will end the try and not insert the corrected data. Here is my code.
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i have maid a program witch has images in it from my hdd. Now when i build my program and send it to other ppl thay cannot see the images. i know this is becaws the path i directed to pull the images from is not on there pc nor do thay have the images lol. so my question is how do i put the images in the actual exe as in the actual program that i have built so all the images and stuff are all in there. so thay only need to run the exe and not have any sub folders to hold the images.
View 1 Repliesso the way I have this working now I'M using System.Collections.Generic.List(Of T) for holding 100's of a structure.Dim Users as New List(Of User)
I was wondering if there was any better way or faster list container or something like this in the .net framework?
I am a first year coding student and we are starting out with Visual Basic. Up until now I have been able to figure everything out, but I have run hard into a wall and I don't feel like I've been taught how to get over it. Here's the thing.
First Form
Contains a list box for products selected, and four text boxes for Subtotal, Tax, Shipping and Total.
Second & Third Forms
Each contain a list box of books to select from which will be added to the first form.[code]....
I feel like I am doing it wrong right out of the gate - as you can see I am going by the item that the user chooses, and adding a constant value that I have pre-defined in a module. Then I add the name of the book to the first form - but here's the issue.That text string doesn't hold a value.SO, when I use the remove button on the first form - the text string removes but the subtotal, tax, shipping and total boxes do not change in the least bit because the item that I removed doesn't retain any value.
I like to create a Structure that could hold 'Yes' or 'No' only; just like a Boolean variable could hold True or False.
View 12 Repliesim using XML as my database and uses dataset to hold the xml. which one do you think is better to backup my xml?
1. write the xml to 2 location, default location and the backup location
dataset.writexml(path1)
dataset.writexml(path2)
2. write the xml to default location and copy it to the backup location
dataset.writexml(path1)
copyfile(path1,path)
if you have a better way of doing it please dont hesitate to share it..
Public Shared Function isMatch(ByVal username As String) As Integer
For i As Integer = 0 To table.length - 1
Dim cellValue As String = table.getRow(i).getCell("Alias")
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I have the code listed above as a translation from a Java snippet. The problem i have is that in Java, my table was stored as a dataset and as such, the methods were easily identifiable by "getRow" and getCell" using specific numbers and column names. However in VB the information is stored in an MS Access database (which i already have an open connection to, called: "_SalesPerformance_AnalyticsToolDatabaseDataSet12") and as such i do not know the correct way in which to iterate through each row in the database, checking a specific column against an already specified variable and then returning an integer based upon the value of a seperate column in the same row.
'Invoice Form
Dim daInvoice As New OleDbDataAdapter()
Dim dsInvoice As New DataSet()
Dim MyDataTable As DataTable
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Error...
Rows cannot be programmatically added to the DataGridView's rows collection when the control is data-bound.
I have an Excel sheet that looks like this.
View 1 Replieshow to add Rows programmatically to the DataGridView's rows collection when the control is data-bound? here is my code but i got error as "Rows cannot be programmatically added to the DataGridView's rows collection when the control is data-bound? "
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If I set a ListBox.Height = ListBox.PreferredHeight when the control is hidden and IntegralHeight = True, then set it visible:
a) Actual Height reduces by typically 3-5 pixels after redraw (but not 1 pixel per item).
b) PreferredHeight does not not appear to give the correct integral of item heights.
Is there a way to make ListBox calculate the correct integral Height before the ListBox is made visible, so it can be correctly pre-positioned from bottom edge?
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
ListBox1.Visible = False
ListBox1.IntegralHeight = True
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I'm trying to make the classic Snake game in VB.NET, but if I hold a key (any key) during the game, after a few seconds the game freezes until I release the key. I've tried lots to fix this, but nothing works, maybe because I don't understand the problem.I'm assuming that when I hold down a key, the Form1_KeyDown function gets called, and when, after a few seconds, the key goes into "I'm being held down" mode, that function is constantly called, so the timers don't get a chance to update. But like I said, I'm probably wrong.
I've been struggling with this for a while. I think this is all the necessary code, please let me know if it isn't.
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I have a bit of a problem. I am using an Access database to hold data for my VB app. In the VB app, I have a data source thats pulling data from the database.
I modified the database today, deleted some tables, added another one, but the data source in the project window does not show these updated changes. I had to reconfigure the datasource with the wizard to get the changes to update.
Is there a way that i can get the data source to update itself when the form loads?
I'm not sure if this is a simple problem or not but it's frustrating me to no end.
I'm using the following code to add my data to the database, and then this to refresh. [code]...
I've never come across this before:I have a series of text boxes. The text of these boxes get set on page load. then I have a submit button that calls a sub to update the table with the new values (text) in the text box. The problem is it is keeping the original text not the text that is CURRENTLY in the textbox. Anyone come across this before? Or know how to get round it?
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