How To Perform A DNS Query
Sep 16, 2009
I've been reading the official DNS RFC [URL].. and looking at articles like this that explain how DNS query packets are structured [URL].. but I'm having a hard time trying to combine the two and actually get to a point where I know what to do
Basically I know that I need to use UDP to send the query and there is only one type of query I actually want to perform - an MX lookup. So I'm hoping that means I dont need to account for a lot of things that anyone creating a complete DNS Resolver would need to implement.
The only experience I have with network communication like this is with protocols that are text based (and use TCP, but I dont think that makes much difference here, if anything UDP should be easier). DNS however is binary based and I just cant figure out how I would know what bytes to send down the wire for a specific MX query..
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Jun 21, 2010
I have created a SELECT FROM WHERE query to perform a search here is my code:
SELECT EmployeeID, DepartmentID, Forename, Surname, Role, Email, Telephone, Extension, Mobile, Photo FROM Employees
WHERE (Forename = ? or ? = '') and (Surname = ? or ? = '') and (Role = ? or ? = '')
I have then put the folllowing code to rung the query within my form:
Me.EmployeesTableAdapter.FillByName(Me.myDataSet.Employees, Me.ForenameTextBox.Text, Me.ForenameTextBox.Text, Me.SurnameTextBox.Text, Me.SurnameTextBox.Text, Me.RoleTextBox.Text, Me.RoleTextBox.Text)
When i search by forename or surname it works fine but when i search by role i get this error..oledbException occured No value given for one or more required parameters.
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Dec 19, 2009
How do I perform an sql query onto a DataTable not a Database table?
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Oct 26, 2011
In my company we use Oracle Applications. Almoust every form in these applications have a common behaviour, which is:
Whenever the forms is opened one can immediately start entering data but one can also press F7, which makes the form to enter in query-mode. You can then fill one or more forms fileds with the data you are searching for and press F8, which executes the query and returns the data into the form. The query mode can be interrupted by pressing Ctrl+Q, returning to data entry mode.
My question is if there is a way of having similar behaviour on building VB forms. I'm using VS 2010.
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Jan 2, 2010
How can i perform order by tCount in this Query?
Public sub StatReport()
Dim Transaction = xmlDataset.Tables("ebus_transactions")
Dim TranCounts = From T In Transaction Take 2 _
[code]....
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Jun 9, 2010
I can achieve in VB what the following C# snippet does but it seems very clunky since I perform a Linq query to obtain the events for the relevant user. Is there a neat way?
ctx.FetchEventsForWhichCurrentUserIsRegistered((op) =>
{
if (!op.HasError)[code]........
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Jul 8, 2009
I want to know if it is possible to perform a mySQL query to get a single record (searched for by ID) and then split each field into a seperate text box.I think im ok with the SQLQuery to get the record. its the splitting it into individual text boxes that im strugling with.
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Aug 19, 2010
Here is the code:
Function getData(ByVal id As String)
Dim reader As SqlClient.SqlDataReader
Dim statement As String
[code].....
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Feb 29, 2012
When Creating a query using the sear Criteria Builder . I keep getting the error : "The schema returned by the new query differs from the base query" what does that mean and how do i avoid this problem in future
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Mar 5, 2010
I just downloaded Windows Search 4. Ive seen several spots that seem to hint that you can access it using .NET but I cant seem to be able to find anything.
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Apr 28, 2010
I am connecting to an Access database and using a parameter query with the LIKE operator to return all rows that match query. The string to search for is taken from a Textbox
sql =
"Select * FROM Allview WHERE Info Like" &
"*" &
CStr(TextBox1.Text) &
"*"
The query does not return any data in vb, but when run from access with same string, there is data returned.The connection to the database is done correctly, as I am able to return data with various other queries.
Partial code :
Dim
con As
New OleDb.OleDbConnection[code]....
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Apr 7, 2012
I am trying to run a query an Access db from VB. The general query which I want to run is
SELECT * FROM Patient WHERE Patient.PatientID = ?
or SELECT * FROM Patient WHERE Patient.PatientLname = ?
I tried using an input box which captured the user input and pass that variable to the query, but that failed. Then I read about writing a function and using that, however, I keep getting an error which says Function not defined, but when stepping through the code, it seems to work. Here is my function: [Code]
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Aug 27, 2010
The database:
"ID (Primary key)" | "Title"
0 | "title1"
[code].....
OK, before adding values to database, we should check if a row exists with this values :)TO do this, creating a Stored Procedure is a best way to deal with the database fastly.So... The problem now is, at the runtime, Miss OleDB throw this error:Microsoft Jet database engine cannot find the input table or query 'IF
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May 29, 2009
i should say hi experts :D . Help me with this pretty code :)
The database:
"ID (Primary key)" | "Title"
0 | "title1"
[code].....
OK, before adding values to database, we should check if a row exists with this values :)TO do this, creating a Stored Procedure is a best way to deal with the database fastly.So... The problem now is, at the runtime, Miss OleDB throw this error:Microsoft Jet database engine cannot find the input table or query 'IF
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Sep 14, 2010
I have to join two main tables, and I need to filter the results by elements in an ASP.NET web form. These filters are created on the fly so I have to use a lot of where extensions to filter the query. I want to execute the query with as optimized SQL as possible.
I am first doing a simple join between TW_Sites and TW_Investigators. Then there are two sub-tables that are involved. TW_InvestigatorToArea and TW_InvestigatorToDisease. While most of the where clauses are working fine, I have found a performance issue that won't be an issue right now, but will be an issue as the table gets bigger.
The arrays DiseaseCategories and DiseaseAreas would be the results of a CheckBoxList result.
Protected Sub LoadResults()
'Get Dictionary of Filters
Dim FilterDictionary As OrderedDictionary = Session.Item("InvestigatorFilterDictionary")
' Initialize LinqToSql
[code]....
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Oct 15, 2011
I created a RDCL in the designer. I would like the User to Determine what is shown in the Report. How can I change the query at runtime? (ex. changing the customer Name)
This is the query that I have in the properties:
SELECT [Date], Address, Customer, Orders
FROM Report_qry
WHERE (Customer= 'JohnDoe')
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Mar 11, 2010
how to take a query that returns a single row of data and load that data into textbox controls.I know about ExecuteScalar but it is only good for a single column of data from the query.
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Mar 19, 2012
Is there a way to set a variable in VB.NET in an IF statement. I would like to do the following:
[Code]...
Is there some way I can get the last "ElseIf" to work? I know I can re-write it to get it to work but is there some syntax that will make it work the way it is?
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Nov 14, 2011
I have loop to create a column of button and now i wish to implemented the eventhandler into all the buttons but is not working. The iteration to create a column of button
[code]...
Most of the solutions were built using C# with silverlight and they seem to be working great. While i having problem by using VB.NET with silverlight
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May 13, 2010
Having read this page, I can't believe that VB.Net has such a terrible performance when it comes to I/O.Is this still true today? How does the .Net Framework 2.0 perform in terms of I/O (that's the version I'm targeting)?
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May 30, 2009
I know .Net and C# pretty well, but never even looked at VB.My problem is: our Win32 COM library is used by a number of clients, and we see that the number of failures is higher for those who use the library from VB (both VB and VB.NET) than for those who use C++, C# or Delphi. One thing about our library is that it is supposed to be used from one thread only - can some threading magic by VB be the cause of failures?
Clients tell us the do not create any extra threads on their own.
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Nov 29, 2010
i have got a value in time span lets say: tsp1= 2 hour 5 minuts i have a another time span variable which contains value like: tsp2= 0 hours , 2 minuts?how can i divide tsp1 by tsp2 so than i can get exact number of times tsp2 divied the tsp1 and how much value is remaining.i am using vs2008?
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Apr 4, 2012
I remember with InterSystems Cache code, you can use indirection to take a string and turn that into real executable code by preceding the string variable with "@". Can this be done in C#.NET or VB.NET code? So I'd like to have a method that would take an arguments array of strings (with one or multiple lines of code), and run that code, assuming it doesn't throw an exception of course. Where am I going with this? I'm trying to write a compiler within .NET code.
SET x="set a=3" XECUTE x ; sets the public variable a to 3
OR SET x="tag1" d @x ; do/call the public subroutine tag1
OR Set Y = "B",@Y = 6 ; sets public variable B = 6
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Dec 13, 2011
I would like to know if its possible, and if so how, to use VB.NET to automate a keyboard shortcut. In the application i am developing, it receives email as a outlook addin and runs various checks and if those checks are positive it inserts information about the message into the database. But i want to be able to tell it that when the subject = "Keyword" to perform Ctrl+Alt+Up for, essentially a prank. However - I can't find anything on this anywhere, all i find is "Custom Short-cuts In VB.NET" and stuff about the KeyDown, KeyUp and KeyPress events.
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Aug 11, 2009
I want to perform serial communication on selecting
.Net Framework2.0--->Visual Basic--->Device application
Presently I am using this code
Imports System.IO.Ports
Imports System.IO.Ports.Serialport
If Button1.Text Is "open port" then
SerialPort1.Open()
Button1.Text="close port"
Button2.Enabled=True
[Code] .....
But I am getting error as
"An unhandled exception of type System.InvalidOperationException occurred in System.dll
Additional Information: The basestream is only available when the port is open".
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May 20, 2009
Duplicate of [URL] I am using this function in vb2005 to colorize a pixel, however when a user chooses a color >50 i begin to lose detail in the image,
[Code]...
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Nov 19, 2008
I tried this but it doesn't work
[code]...
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Nov 24, 2010
I'm trying to build a four step process into a VB.NET GUI. The application transfers objects from AppA to AppB.
The application will follow these steps:
User constructs a general query in the GUI to identify which AppA objects to transfer. Model gets queryResults, datagrid in View lists each result User deselects items not to be transferred to AppB Model transfers selected items
how this should work. I've have the following functions implemented in the model, but don't know the MVC-way to tie them into my GUI:
Function getQueryResults(queryParams) as Items
Function transferItems(items)
Do I keep the Items data structure in the model?
How do I remove deselected from the Items data structure without building logic into the view?
Both of the above functions take time, how can I design thing to allow me to BackgroundWorker the model's functions?
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Jan 7, 2012
What i want is i have a listbox in form a, which display data from database, for example it's displaying student ID.
after user double click on the id, form b will "show" and load that particular informations.so should i do that action in ListBox1_DoubleClick or form b_load?
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Feb 16, 2010
i'm using a datagridview to display the records which are filled in my dataset. however i need to perform paging to display only selected numer of records (e.g: display only 10 records per page) and by using the buttons (like: FirstPage, NextPage, PreviousPage, Last Page) allow users to nevigate through the records. and possibily display the total number of records in my dataset (e.g: |< last <Next 10/100 previous> first >| ) this might sound very simple but i'm new in .net and so far whatever source code i found in google is moslty written in C# which i don't know.
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