I constantly find myself having to do code similar to the following.[code]Is there anyway to check for both on a single line? When i'm checking a condition for a great number of answers, I sometimes end up with conditionals 6-sets deep. If i check for null first, an error still pops up, even though VB shouldn't check since the first condition failed. i.e.[code]
View 8 RepliesHow do you do nested recordset loops in ADO.NET? In ADO, you could just open one firehose cursor for the outer loop and a static, client-side, read-only cursor for the inner loop and nest the loops. But you can only open one DataReader at a time and Datasets aren't read-only.
'Classic ADO Code
Dim rsOuter as New ADODB.Recordset
Dim rsInner as New ADODB.Recordset
[code]....
how to create this sequence using a for loop and/or nested for loops?
1
2
3
[Code].....
I'd like to be able to do something like this:
Dim newdata(,) As String = New String(,) { _
{"foo", "bar"}, _
{"fum", "baz"} _
[code]....
If I change the outer loop to:
For Each str() As String In newdata
It builds ok but I don't get what I want. The outer loop process the elements of newdata as a 1d array and the inner loop sees each character of the strings from the outer loop.So...is there a way to use the for each structure and process a 2d string array? If so, what should I change? If not, what is the best alternative?
I am trying to write a program that using a nested do while loop and If/If Else statement to draw a shape, and also using a nested do until and If/ElseIf statement to draw another shape.
View 18 RepliesToday is not one of those days. I know there is an elegant solution to this problem, but I cannot see the endgame. Does anyone have any tips for making this snippet more elegant? It's a very basic example, but one that I think is common programming challenge. If I have unknown number of lists of string variables of unknown length (It is unknown to me until runtime), how can I use just one loop or a loop plus a nested loop to create a matrice of the values?Easy to re-create. Create a VB.NET Form application, drag over two richtext boxes and a button, then paste this into the form class
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[code].....
I want to write two nested loops and inside them "two if statements" when I write an Else statement which has a messagebox saying that ID is not found.. it repeated many times depending on the for loops. I only want to be displayed once !!! but when I wrote my code like this (using exit sub), the message appears when the condition is right and appears when the condition is wrong. I tried to move this statement somewhere else but still I have problems with it.
With EMPDataSet
For I = 0 To .Personal.Rows.Count - 1
For j = 0 To .Work.Rows.Count - 1
If EMP_CPR = .Personal.Rows(I).Item("CPR") Then
txtName.Text = .Personal.Rows(I).Item("Full_Name")
[Code] .....
I'm trying to implement parallel computing using .NET 4 on an asp.net website housed on a clustered server consisting of 6-8 dual core servers. My original script contains two nested For...Next loops iterating through a range of values in a grid of x by y.
For each point in the grid (x,y), we should perform a computationally intensive subroutine called MakePartsMatrix which accesses a SQL server database with dataviews and manipulating the local variable "unfilled" which is passed in ByRef.
Without the parallel implementation, the nested for loops work fine except its slow -- taking about 60 seconds to run.
When I parallelize the outer For loop, the script is about 50% faster, completing its calculations in 20-30 seconds which is great. However, I have noticed that the parallelization causes random parts of the grid to be either completely skipped (eg, grid (1,5) is never evaluated by the MakePartsMatrix), or some points in the grid (eg, x=10 & y=5) to be evaluated multiple times, resulting in duplicate work.
When I parallelized only the inner For Loop, the script execution time also improves by 50%, but now the last row (y-1) in the grid is skipped entirely and the results in "unfilled" are completely wrong.
When I comment out the "MakePartsMatrix" subroutine, the parallellization (either inner or outer For loops) does appear to visit every point of the grid (x,y) once, and only once.
Dim ConcurrentListofResults As ConcurrentQueue(Of FindBestResults)
ConcurrentListofResults = New ConcurrentQueue(Of FindBestResults)
Dim FBSResultsItem As FindBestResults
[Code].....
I have an arraylist of a "Doctor" class containing Firstname, Lastname,etc. Some elements in this arraylist may be duplicates of others. I am trying to iterate through the arraylist and search for duplicates. Once i find a duplicate i want BOTH duplicates put into another array and removed from the original array.
here is my function
Public Function createArrayOfDuplicatesAndRemove(ByVal st As ArrayList)
Dim duplicates As New ArrayList()
Dim i, j As Integer
[code]....
How could something be out of range if i start at the end and work to the front?
I am trying to code something with nested for loop with the following format:
[CODE]...........
However when the program hits the last value of 'For loop 1', the nested for loops seem to only trigger once instead of the number of times that i specified.
Private Sub populatedgv1()
'setup temptable to store Server data
Dim m_table As New DataTable
[CODE]........................
I have a fairly simple piece of code:
Private _PurchaseDelivery as PurchaseDelivery
Protected Overrides Sub InsertItem(ByVal index As Integer, ByVal item As PurchaseDeliveryItem)
[Code]....
Which is inside a class which overrides a custom list base. The code is occassionaly throwing an unhandled exception, System.NullReferenceException, on this line when used in production:
If _PurchaseDelivery IsNot Nothing AndAlso _PurchaseDelivery.DefaultSKUBinID.HasValue Then
DeafultSKUBinID is declared as an Integer? (Nullable Int) in the PurchaseDelivery class. I cannot see what might be causing this error, why would this be returning an error?
So I have some vb.net code, and I have a nested For loop inside a For loop, and then I have EXIT FOR statement, will it break out of one loop, or the whole chain?
View 2 RepliesThis must've have been asked before but I couldn't locate it. In a mixed code project (VB and C#) we were debugging some old Visual Basic code where a statement as follows could be found:
If Request.Params("xxx") <> "" Then
'do something
I considered this a bug as Request.Params could be null, in which case the statement would've become false which wasn't the idea. So I thought. I just found out, -- probably for the tenth time and I will keep forgetting -- that the following two statements are not equal, while Nothing in VB should be equal to null in C# (thought I):
if(String.Empty == null) // always false
If String.Empty = Nothing Then ' always true
Should I dismiss this as a typical Microsoft backward compatibility effort, or should I consider this a huge error in the VB.NET compiler? Does anybody know the Microsoftean opinion on this oddity?
How do i check if the dataset is empty? I wrote the following code:
[Code]...
I have a field that I want to check to see if it has a value or not. But my code is not working. I am using:[code]
View 9 RepliesIn my application I load a CheckedListBox from text file apart from looking at the form, how can I trap the error of not completing the action?
View 1 RepliesHow will I check that the dynamic textboxes is empty;
Here's the code:
Imports System.Data
Imports System.Data.SqlClient
Public Class FunctionProcessor
Dim objcmd As New SqlCommand
[code]....
I have an RDLC report that I am rendering directly to the Response Stream as PDF (rather than using the ReportViewer). In the code that renders the report, it's DataSource is bound to a List(Of ClassA) objects defined in a custom assembly. This seems to work for the most part. My problem is that I can't seem to handle the situation where a nested object is null. For example, given ClassA and ClassB (the nested object) defined as follows:
Public Class ClassA
Public Id As Integer
Public Name As String
[Code]....
the report displays "#Error" if TheNestedObject is null. If TheNestedObject is not null, it correctly displays the Name.
i have a date control on form (vb.net) and by default its value is current date. i want to make its value to null or empty so that no date is shown and user choose from the drop down date calendar.
View 9 RepliesI am getting the attached error when any cell in a row is empty. How to avoid this error and to accept the null values?
View 4 Replieschecking im my textbox contains null valuefor example i have ten textbox how do i know if a textbox has no text in it?then gotfocus to that specific textbox?
View 3 RepliesI'm using Visual Basic .NET to work with a USB HID device.Most of the time, I can receive data from it perfectly... but one out of every thousand transfers or so, my code will think it has received data when it actually hasn't.The device writes to an array of bytes. I wanted to check to see if the received packet is empty, by doing something like this:
If myDevice.dataPacket(1) <> Nothing then
myDevice.rxDataReady = False
[code].....
ve a simple vb code similar to the below,
Function getvalue (ByVal Val as double) As string
Dim Num as Integer
Dim Prd as double
[code].....
Is there anyway to check for a null here before it reaches this part of the code? tmpLabelData(0) = m_node.Item("CONTAINER_NAME").InnerText. Some XML has it while others do not. I cant seem to find a nice way to handle a null on these?
View 1 RepliesI'm querying a SQL DB and sometimes the result is Null, so I thought I would test this but my code results in an error "Data is Null. This method or property cannot be called on Null values."
Here is a snipet of my code:
For i = 5 To 6
cmd = New MySqlCommand(query2t & i, db)
rdr = cmd.ExecuteReader()
rdr.Read()
If Not IsDBNull(rdr.GetUInt32(0)) Then
[Code] ......
I have some code that is meant to check the length of the values in the text boxes, and if any of the boxes has no content the length of the string is 0 (or null). Here is the code:
If (Len(Form_MainScreen.Ctl48.Value) Or Len(Form_MainScreen.Ctl49.Value) Or _
Len(Form_MainScreen.Ctl50.Value) Or Len(Form_MainScreen.Ctl51.Value) Or _
[code]....
When one string is blank, the length check becomes "null" and so does the whole statement.But if the length checks are all not null, the if statement becomes a "1" and then procedes to execute the Do X procedure again.
I'm writing a program for my class, which pretty much is an energy cost calculator. It takes 4 inputs from 4 text boxes and multiplies them, and the result is the cost. Well, now I have to come up with a way to check for empty text boxes and display a prompt to enter a number. I've tried inserting multiple codes to display a prompt and to no avail nothing has worked, I also receive the error "when casting from a number, the value must be a number less than infinity" error.
View 3 Replies I am getting product id value some times null and empty from databasehere how i check if valule null and empty
productid = IIf(IsDBNull(TempDT.Rows(0).Item("productid")) =
True,
"", TempDT.Rows(0).Item("productid"))
[code].....
I'm deserializing some XML from an old application into an object in my current application. The old XML often has empty elements (<SomeElement />) which are currently deserialized as empty strings (""). I agree that this is the most appropriate behaviour, but it is a minor irritant; I'd rather they were deserialized as Nothing or ideally ignored - the effect would be the same. Is there a means of ignoring these elements? Or can I have them deserialized as Nothing?
View 2 RepliesI have an ASP.NET application that crashes when a null date value is returned.
The code line is:
excelWorksheet.Cells("A" & xlRowCounter).Value = IIf(IsDBNull(dRow("sysdate")), "", Format(dRow("sysdate"), "MM/dd/yyyy"))
Error message:
ERROR: System.ArgumentException: Argument 'Expression' is not a valid value.
How would I check for a null date, and replace it with "" in my app ?