I'm having trouble passing strings to a C++ DLL from my vb.net program. I get constant Read/Write memory error exceptions. My C++ code is as follows:
Code:
char * get_signal_desc(char * dev)
{
bool status;
char * desc;
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I ran into an error when trying to do this:
Code: ChartBuffer = GetCurrentChart(ChartBuffer) The error says Conversion from type 'Integer()' to type 'Integer' is not valid.
Apparently I have some type casting issues, the problem is I'm not trying to cast any types at all. I'm trying to set one array chartbuffer equal to the array returned from GetCurrentChart.
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In the constructor of this class I am trying to set the buffer equal to the loaded chart because if I try to write information to a buffer that isn't already initialized, and then save it, it will overwrite stuff that might already be saved in the file as 0's or something, and I don't want it to do that. To prevent this from happening I'm simply going to initialize the buffer in the constructor by setting it equal to the loaded chart. Finally after that is all done I can write new information to the buffer and save it to the file without writing a mostly empty buffer (full of zero's) to the chart that is saved with information in it already.
I am storing some user settings by the very handy My.Settings classes in VB.net and it seems to be taking a mixed case string (a file path and filename) and returns it in all upper case.
View 2 RepliesI am trying to call an external C++ function using VB.NET (answers in C# are fine, I can convert back) which returns a list of device names. This comes in the form of a pointer to a null-terminated array of null-terminated char arrays (correct me if I've misunderstood what I'm dealing with) with a function signature:
long GetNames(char*** names)
Most of the answers to similar questions I've found have involved something more like:
long GetNames(char** names, int length)
It appears from what I've read that I need to give it an IntPtr but I'm uncertain as to how this should be initialized, and in my case I don't know the length of the array. At the moment, in the VB module, I have:
<DllImport("MyExternal.dll", CallingConvention:=CallingConvention.Cdecl)> _
Function GetNames(ByRef names as IntPtr) As UInteger
End Function
I've tried calling the function by passing an IntPtr initialized as IntPtr.Zero or using Marshall.AllocHGlobal, but I always get an AccessViolationException.
Any ideas on how I should be calling this function and how I get the return value into a managed string array would be greatly appreciated.
EDIT: I've found a sample function call in native C as follows:
char **tmplist;
GetNames(&tmplist)
I have two executables that access a DLL containing Data Access Layer objects Each exe can have a different config containing info on server and database name, connection string etc.How do I pass the config info to the DAL objects?
Obviously I can pass the config strings to the DAL objects every time I instanciate one, but that seems messy and repetitive as every class in the DAL will require Properties for the Config strings..if there is a way for the instanciated DAL objects to read some properties from the calling object without me having to pass them explicitly?
Reading [URL] made me wonder whether the comments in there did apply to Strings in terms of performance. Since strings are copied before being passed, isn't it much more efficient (if the callee doesn't need a copy of string course) to pass strings ByRef?
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I have created a webservice in VB.NET
<WebMethod(Description:="This
method will return object Values (in an array of String)for all objects (in an array og String)",
Enablesession:=False)>
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Error 1 Value of type '1-dimensional array of String' cannot be converted to 'TestUse_SEdkVistaWebService.JF_WebService.ArrayOfString'
I need to pass two variables/strings to a background worker at the same time. he background worker needs to return the first variable, and the time consuming boolean result of the second variable.From what I have read, I can only pass an object that contains multiple variables.This is where I get confused
View 1 RepliesIt checks if the webpage in the web browser control has crashed. The website crashes alot. I want to acomplish this by checking the text of the webpage for vital keywords such as "ERROR" or "Could not connect:" or "An error occured. Returning to the autowatch system in 60 seconds..." The code I have so far is below.
Dim myText As String = Me.WebBrowser1.Document.Body.InnerText
If myText.Trim().StartsWith("Could not connect:") Then
WebBrowser1.Navigate("http://www.enhanceviews.net/view/config_check.php")[code]....
The page refreshes every 5 to 120 seconds. The timer gets activated 10 seconds into the program's launch. It refeshes the code above every 5 seconds(to minimize CPU usage). However, it crashes and gives the error "NullReferenceException was unhandled". This could be because the page keeps on refreshing or the page is php and has 2 iframes. How do I fix this?
Say I have a List(Of Tag) with Tag being an object. One member of Tag, Tag.Description, is a string, and I want to make a comma-separated concatenation of the Description members.Is there an easier way to do this than to read the Description members into a List(Of String) and then use the Join function?
View 2 RepliesI have an ASP.NET web application (VB.NET) using an Oracle database. On an insert, I need to get the identity of the inserted row back. I am trying to use RETURNING, but I keep getting a value of 1 returned.
Dim strInsert As String = "INSERT INTO L.TRANSACTIONS (LOCATION_KEY, TRANS_CREATOR, TRANS_EMAIL, TRANS_PHONE) VALUES (:location_key, :trans_creator, :trans_email, :trans_phone) RETURNING TRANS_ID INTO :ukey"
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My brain may just be fried since it's the end of the semester, but my teacher kicked this back to fix and resubmit...she said that I am "returning the name of your function rather than your variable name".
Here is my code for all 3 forms.
code:
These are forms to calculate the cost of getting a cell phone package.
I am working on a UDP Client/Server, and currently i have them sending back and forth strings, which i convert to bytes, and then open the bytes to read. I want to now send an Object instead of those strings, which includes multiple unsigned integers and strings.
View 39 RepliesI have a list of strings. For each string in that list, I want to prepend another string. I wrote a method to do it, but I was wondering if there was something already in .NET I could use to do this. It seems like something that could be built in, but I was not able to find anything.
Here is the method I wrote:
Private Function PrependToAllInList(ByRef inputList As List(Of String), ByRef prependString As String) As List(Of String)
Dim returnList As List(Of String) = New List(Of String)
For Each inputString As String In inputList
returnList.Add(String.Format("{0}{1}", prependString, inputString))
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It works, but I would rather use built in functions whenever possible.
I'm migrating from VB6 to VB.NET, in hence my questions below:
I have to write a function that returns array of strings.
How can I initiate it to empty array? I need it since I have to check if it's empty array after it returns from this function.
Is list of arrays better for this purpose? If I use a list - Is it empty when it firstly defined? How can I check it it's empty?
I have been looking for examples to find the string between two strings. This top one works fine;
Public Sub ReadData(ByRef keywordStart As String, ByRef keywordEnd As String, ByVal filename As String)
Using reader = New StreamReader(filename)
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Now the first one is fine - Ext_Volume is result of the string between the strings <Volume> and </Volume>. <Volume> and </Volume> are unique so this is straight forward.
However the second one - "^FDExp:" is unique, but "^FS" is not unique. There are occurances of "^FS" before and after "^FDExp:".
How do I get the string to search AFTER the occurrence, not before etc?
Dim str As String
Dim str2 As Array
str = "blabla duhduh"
str2 = str.Split(" ")
Say the string is something like
bla bla bla bla (cat) bladfdskdfd dsgdsdksf (dog)
dfdshfdskdskfsdfkhsdf sdkfhdsfkdf (kathy) fdsfhdskfhdsfkd (doggy)
I want a generic.list (of string) containing
cat
dog
kathy
doggy
How to do that with regular expression in vb.net
Later I want to do something more complicated like getting all strings between "url":" and ", from this strings
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Is there an easy way to find a certain string within a string and then return the strings that you find as an array?I have written this:
Public Function FindStrings(ByVal strSourceString As String, ByVal strStartString As String, ByVal strEndString As String) As String()
Dim StringStartposition As Integer
Dim StringEndPosition As Integer
Dim Currentposition As Integer = 1
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I have this string called time. It's value is in this format: HH:MM:SS The numbers change, but the format stays the same. I want to separtate the code into 3 strings Hour, Minutes, Seconds.
View 2 RepliesI have a DataGridView that has some columns with dates. It binds to an in-memory Datatable which gets loaded from an string array of data passed back from the backend Some of the rows returned have nulls for the date columns. Solution 1: If I define the Date column in the DataTable as "string" I can easily convert those nulls to empty strings and display it in the grid as empty strings (desired results). However, if the user clicks on the date column header to sort by date, it doesn't order the rows as you want. You get a purely string sort order. Not acceptable
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Here's the weird problem I am trying to solve but cannot get my mind around it. In a text box 1, the user enters 2 or more strings separated by comma. then in text box 2, the user enter 1 or more strings separated by comma. The output then puts the strings from text box 2 between the strings in text box 1
Example:
TextBox1 = visual basic, java, perl
TextBox2 = is better, compared to
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So I have a pretty simple UDF written in visual basic for use in excel. It calculates your approx. taxes. Lets say I use it as such: =Taxes(I23-I18,I24-I20,"Married")
If I type this in it works great. Now if I save the sheet and restart excel the cell now says #VALUE! If I select the formula and hit enter once again it recalculates it fine. What am I doing wrong? Application.Volatile shouldn't be needed but I was trying ideas. [Code]
This might seem like an insanely easy question, but I cant seem to find an answer anywhere to it. I'd like to think that I am decent at VB but while I was learning javascript the other day I found something that seemed awesome and now I cant figure out how to do it in VB.in javascript it looks like this
var someValue = getThatValue()Its both calling and setting the value from the getThatValue() sub. what is the VB equivalent?
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I have a piece of code that checks a time and then adds hours based on the daylight savings time value.
Dim CommentDateTime as Date = "11/2/2010 8:21:42 PM"
If CommentDateTime.IsDaylightSavingTime Then
'do something
Else
'do something else
End If
The problem that I'm having is that IsDaylightSavingTime behaves differently on the production server than it does on the development.On the development server the case is TRUE, but on the production it is false.
Both servers are running the same OS and are both running .NET 3.5
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I have two different GetConstructors(), one is returning what it should be returning the other however is returning nothing. ItemName is BSRPTReportPerformanceSubcontractorRating
The first one which is returning what it properly should is:
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I have an XML file that sits on the hard drive of a Server running my Web Service. I need to access that file from another application.
This is my method on my Web Service
Public Function getXMLFile()
Dim xmlDocument As System.Xml.XmlDocument
xmlDocument = New System.Xml.XmlDocument()
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This is caused when I try to return the xmlDocument object
From the information I gathered, it's like SOAP wants to wrap my XML in more XML and stops me from doing that.
How do I go about getting the XML File from my Web Service if I can't return XML?
i am new to VB programming, actually this is my first time with VB any ways here is my situation that is driving me mad
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I am creating a message box in VB8 for an error. I created the message box and everything works. The message box returns a value of 0 which is the default one. Where does it return 0 to. Or do you have to tell it where to return it.
View 2 RepliesThanks William, that was the ticket. Had to assign the name property on both ends [DataTable.TableName].
On a side note here: There appears to be some school of thought (no offense Marc) that the following statement is always true:
"Everything in the world can and should be made into an object."
It is, simply, not always true. There are cases where you cannot cram your 'object' into any cookie-cutter or class no matter how you try to customize it. For me to objectize this beast, I'd have to create roughly 4,000 objects. I don't have time to do that, and yet this project must run as a service. Frankly I think the developers at MickeySoft need to get out more into the real world, and see for themselves that although theory is great it does not represent true-life challenges. I am all for working with objects for the obvious benefits, but there is a reality that universals do not exist. In my trade, even 'most of the time' rarely happens.
Before they push out a new technology set, and cease support of an old one, they need to make sure that the new technology has the same capabilities the old one had.
For the record: The people who believe the above statement to be true are also the same people who would refuse to take the project I'm currently working on.
Just the same -- thank you both for your time, efforts and opinions!
I'm trying to create a WCF function that will return a table to my console testing app. I am a total noob. The data is 2-dimensional and looks like this:
23 Letter
42 Another Letter
43 Document
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...Of course, it won't work. I just need to get the WCF to pass a basic table to my console application. The execute SQL seems to work just fine, I just can't get the data back to my application.