I am having trouble constructing an SQL UPDATE string to do the following.
Table A (field, type) Table B
ID (key) Integer ID (key) Integer
ParentID Integer IssueID Integer
Number String ParentID Integer
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constructing a waveform in vb.net. Can maybe someone give me a hint of how to make one? (a bit of code would be nice) I already know that to generate a waveform, you need a timer, if there anything else?
View 1 RepliesIs there a way to dynamically create properties at runtime in VB .NET using introspection?
e.g. Suppose I had a class
Public Class Foo
Public Property Bar() As String
get
...
end get
[code]....
Is there a way to create property Bar at runtime?
I've been working in .NET for some time now, but occasionally I still get confused by a disparity between the framework and my prior experience in C++.In .NET, all objects are either value types or reference types. Reference types are allocated on the heap while value types are allocated on the stack (in the current CLR implementation, anyway). I get that. However, at least in VB.NET, you can still define a constructor on a value type.
Public Structure Coordinates
Public x As Integer
Public y As Integer
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I'm not entirely sure what to call what C# does, so I haven't had any luck searching for the VB.Net equivalent syntax (if it exists, which I suspect it probably doesn't).
In c#, you can do this:
public void DoSomething() {
new MyHelper().DoIt(); // works just fine
}
But as far as I can tell, in VB.Net, you must assign the helper object to a local variable or you just get a syntax error:
Public Sub DoSomething()
New MyHelper().DoIt() ' won't compile
End Sub
Just one of those curiosity things I run into from day to day working on mixed language projects - often there is a VB.Net equivalent which uses less than obvious syntax. Anyone?
I've used VB.net for several years now, but keep coming across little quirks that I don't know how to work around. Curiosity finally got the best of me, so I ask now: is there a way to create an object without assigning it?For example, say I have an Engine class, that I want to instantiate and have it immediately do whatever it needs to do. If there's nothing I need to do with Engine after creating it, I have, till now, done something like:dim myEngine as new Engine()Is there a way to avoid the "dim myEngine as" part? You certainly can in Java. I could just create an object with "new Engine()" in java and not assign it to anything.
Why do I need this? Because often I want to create a delegate object (hence I called it "engine") that performs some functionality, but otherwise I don't need to ever reference it. I used to have such objects have a "public sub perform", but have found that cumbersome -- I'd rather just create the object and not worry about remembering to call its perform method. And I find it aesthetically displeasing to create references to objects that I don't intend to use
I have a specific problem that I have not yet found an answer to. Basically I need to pass a list of numbers into a function do some math and return them. I can pass one number at a time without a problem, however when I want to pass in an array I start to have issues. My VB.net code looks like this...
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I have to set GridView.DataKeyNames(This is really a question about the syntax for a string array, in VB.Net.)I am discovering the PrimaryKey columns names from within a loop, ie:For Each fld As IEntityField In Me.llbDataSource.EntityCollection(0).PrimaryKeyFields'fld.Name ' this is where the column name is stored, so I have to get this into an array Next..[code]So, basically, how does one declare a string array (as required by GridView.DataKeyNames), and then populate the elements of the array from within a loop?
View 3 RepliesI am constructing a search function in a class to be used by several of our asp pages. The idea is simple, take a search term from the user and query the database for the item. Currently I am doing this the wrong way, which is vulnerable to SQL injection attacks (and ELMAH is in there to save the day if something goes wrong):
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The problem is since I am using a like statement, I need to be able to have % on either side of the search word, and I can't seem to do that with '%:searchterm%', it just gives an error of ORA-01036: illegal variable name/number.Can I parameterize but still have my flexible like statement be a part of it?
Using MS Visual Studio 2010 Express, when trying to debug, the build finishes and the following error below appears. It doesn't seem to effect the running of the program.
The error is:
An exception was encountered while constructing the content of this frame. This information is also logged by running the application with the /log parameter on the command line, which stores results in "C:Documents and SettingsCorkyApplication
DataMicrosoftVBExpress10.0ActivityLog.xml".
Exception details:
System.Runtime.InteropServices.COMException (0x80040154): Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))[code].....
I can't find the "ActivityLog.xml" file the message references.
How it's possible to add/update a date(or other string) to the database when a user connects? i use in this
MySqlConnection = New MySqlConnection
MySqlConnection.ConnectionString = "server=***; Port=***; user id =***; password=***; database=***"
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I get a syntax error while trying to update a datatable using this syntax string:"SELECT * FROM ClientContacts WHERE MembershipID = '" & stringVariable & "' "
View 6 RepliesI have a connection string for my SQL database connection called my.settings.GCRConnectionString which was created when I created my dataset for the application. I want to change the value of the connection string but it give me an error saying it is ready only. Is there a way to update my connection string during the run-time?
View 4 RepliesI have an Article object with the following properties:
Article Name (varchar)
Article Body (varchar)
Article Tags (varchar)
The Article Tags is a space delimited string of text values that a user has tagged the aritlce with. The 3 properties are passed to a stored procedure.
I now want to do the following:
1) Insert the Article Name and Article Body in the dbo.Articles table and return the article id
2) Insert each value of the Article Tags string in the dbo.Tags table as a separate row but first check for duplicates. If duplicate then return the tagid of existing record, if new record then return the new tagid
3) insert the article id and each tagid as a separate row in the dbo.TagMap table
I need to know the best approach to how I would accomplish this, also being conscious that it does not cost too much in performance.
I have a problem with the code below as a SQL command string. Note: Using .Net Framework 4.0 in Visual Studio 10 Professional. Database is a Microsoft Access file. The idea is that this SQL command string will update a password within my database. Also note that I have tried the string below with and without the ";" at the end and it does not work either way. The problem is most likely extremely obvious, but I can't seem to find it. I have commented below the code what each part of the String is.
"UPDATE Users SET Password='" & tbx1.Text & "' WHERE Username = '" & sUsername & "';"
' Users is my Table name within the Database.
' Password is the field that I want to edit within the Users table.
' tbx1.Text is where the password is stored within a text box.
' Username is the field which I would like to compare with sUsername which is a variable within the code.
Solution was square brackets, Command string now looks like this:
"UPDATE Users SET [Password]='" & tbx1.Text & "' WHERE [Username]= '" & sUsername & "'"
i'm trying to refresh a few form checkboxes based on text typed into machinetxt.text with what is currently stored in the database. i put this into the refresh button click event. here is my code:
Private Sub machinerefreshbutton_click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles machinerefreshbutton.Click
Dim mycon As SqlCeConnection
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i've tried tweaking the select statement but it still gives the error that the machinetxt.text string is not found in the database. Even though i type it in exactly as shown in the database.
is there way to update having quote string eg. drug's name ('s) in vb text field ' this corrector REFUSING TO UPDATE TO DATABASE. this kinds of error always comes up Incorect Syntax Near 'S'.Unclosed Quotation Mark After character string '))'.
View 3 RepliesThis is what I have for code:
Private Sub restoreDatabase(ByVal dbName As String)
Dim newDbName As String
newDbName = dbName.Substring(dbName.LastIndexOf("_") + 1)
My.Forms.portfolioGenerator.Close()
[Code] .....
It seems like it should be pretty simple, I take in a file name as a parameter, create a new name for it, delete it, then try to copy it back from an older version of the same file, and update the connection string. However, it continually tells me that "The file 'filenamehere' already exists." If I set overwrite to true then it goes through just fine, except it doesn't actually copy the file. Obviously I also check the folder, and the file does in fact Not exist...I've also checked all the file paths and what-not, they are all accurate.
I have following code which is not working and giving Null Reference Exception.
Dim x As New XmlDocument
x.LoadXml("<HostTxnAmt>123C,</HostTxnAmt> ")
x.InnerText = "123"
MessageBox.Show("Done")
I need to simply update text from xml node and save it back into string.
I am having some issues with a parameterized SQL Lite query. I can't seem to get the SQL Lite Parameter to accept the String value
Using cmd As SQLiteCommand = pConn.CreateCommand()
If tblLang = "en" Then
cmd.CommandText = "UPDATE [AT_Strings] SET [Data] = @tblData + 1 WHERE [RecordID] = @ID AND [language] = @tblLang1"
Dim tblData As New SQLiteParameter("@tblData")
[code]....
The error is as follows....Unable to cast object of type 'System.String' to type 'System.Data.SQLite.SQLiteParameter'.Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidCastException: Unable to cast object of type 'System.String' to type 'System.Data.SQLite.SQLiteParameter'.
Source Error:
Line 283: Dim ID As New SQLiteParameter("@ID")
Line 284: Dim tblLang1 As New SQLiteParameter("@tblLang1")
ERROR on Line 285...
Line 285: cmd.Parameters.Add(dataText)
I doing some maintenance work on a vb .net web app and receive a system.formatexception input string was not in a correct format error after I update a row from a GridView control. The database update returns fine and I've stepped through the code and it never throws an error but when execution finishes and returns to the browser I get the following. I turned on the feature to break when an exception occurs but it never does break. Any suggestions? [Code]
View 2 RepliesI have a gridview in which when I click edit, update, and cancel button comes. I have a variable named status. If status=false then update should change to insert and if status=true then update should be update itself.
<asp:TemplateField >
<ItemTemplate>
<asp:LinkButton ID="lnkEdit" runat="server" CommandName="Edit" Text="Edit">
</asp:LinkButton>
[code].....
We have two update panels on our webpage. Now first update panel is having button cancel. While second update panel is having a file upload control.Now if the user uploads a file that is going to upload in about 2 mins, and in between, say after 30 seconds the user clicks the cancel button, the upload taking place in update panel 2 should stop.
View 2 RepliesHere textbox11 contains a float value and combo box contains a string do i have to put text or selected item
cmd.CommandType = "UPDATE BALANCE SET OBBALANCE = '"& TextBox11.Text &"' WHERE CUSTOMERNAME = "& ComboBox1.Text & " "
It gives the following error: Operator '&' is not defined for string " UPDATE BALANCE SET OBBALANCE = " and type 'DataRowView'.
I used to take a string from a text box in vb.net and pass it to a sql query to update or insert in a database.I faced a problem when the set of characters in the text box contain " ' " (single quote), it throws a error "unclosed quotation mark".
View 3 Repliesupdate statement, i am trying to update a row within a access 2007 database here is my code.
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I am using vb.net with access database. I am using sql. How can i update database with the value 40'6"(Feet and inches values)
View 5 RepliesI have an issue with a data base updating it won't update for me in debgging mode it is stopping here on this bit of code which is highlighted in red. the error which comes up is .(update requires a valid update command when passed datarow collection with modified rows.)
Public Sub UpdateDataSource(ByVal ChangedRows As database.dataset1)
Try
'The data source only needs to be updated if there are changes pending.
If (Not (ChangedRows) Is Nothing) Then
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I am using an update panel and when I click a button it will update all the panels. updapanel1.update() is very simple, but my data is not updating unless I hit the button twice. My gridviews shows data for a selected user, and then all the grids reflect that users data. works fine all the update panels work for the gridviews. Now for somereason when i try to do a row count and update the panel with the summary, it does not work, i get either the previous users summary or if i hit update again for the same user i get the correct data.
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What is wrong with this code. It does not update the access database and no error.
Dim conn As New OleDbConnection
Dim sqlQRY As String = "SELECT * FROM StdMaster WHERE StuNo = " & txtStudentNo.Text & " ORDER BY StuNo"
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