VS 2008 - Class With Attribute / Dealing With DBNull Values
Dec 22, 2010
I wonder, what is the most elegant way of dealing with the dbnull situation. I have a class, with attribute, let's say: "End_Date", which is being read from database. Type of this variant should be date, but as it's the "End_Date", there might be the situation that something haven't ended yet, and in the database in this field I have a null value.
Right now a deal with the problem this way:
Dim mEnd_Date
...
Public Property End_Date ()
Get
End_Date = mEnd_Date
End Get
Set(ByVal value)
mEnd_Date = value
End Set
End Property
But I am not sure if that's a good way as I don't declare variants as any datatype?
I have valued pairs, attributes names and values in one hand, and I have an object with attributes. I need to set the values of those attributes. I need something like [code]
Some tables I am dealing with have null values and are throwing errors. So far ive tried a few solutions to deal with the nulls with no success.Here are the code samples from my efforts so far;
If (r("datemodified").Equals(DBNull.Value)) Then datemodified = String.Empty Else[code]....
i have ran the query and it is working ok (i.e all the cols exist)
Dim myreader As SqlDataReader = cmd.ExecuteReader 'read information from the database and give the values to the arguments(column_1, and column_2) While myreader.Read column_1 = myreader.GetString(1) column_2 = myreader.GetString(2) ..... I get an error when the data returned from myreader.GetString(2) is NULL. How do I check for nulls before assigning column_2 a value?
I am looping thorugh a datatable and and printing each row to the console and I keep on getting a dbnull error. I inserted an if statement in my loop to try and catch it, but I can't seem to get it to work.
I was able to do this via a SELECT CASE statement, however I'm always trying to improve my code writing and was wondering if there was a better approach. Here's the scenario:Each document has x custom fields on it.There's y number of documentsHowever there's only 21 distinct custom fields, but they can obviously have n different combinations of them depending on the form.So here's what I did, I created an object called CustomFields like so:
Private Class CustomFields Public agentaddress As String Public agentattorney As String
I have a Class CButtonCreate without get & set Methode. But i wanna use the Attribute "string newFileName" from the Class CButtonCreate in a other Class thats Class WriteToFile. How can use the Attribute newFileName in the Class WriteToFile?
class CButtonCreate { // Create a Folder && SubFolder from the tbProject public void CreateFolder(string MyFolderName, string Mytbs, string MytbRevision, string MyTestSystem) {
I'm trying to force an inherited class to use a custom attribute. I'm creating a class library where the user who wants to create an item will do so, but be forced to add an attribute (or visual studio will automatically add the default attribute) to their inherited class. Here is what I'm hoping to achieve:
BaseClass.vb: <CustomAttribute(10)> _ Public Class BaseClass End Class MyClass.vb:
Newbie looking for help on getting xml http response in vb.net this is what im looking to do ,getting these attributes values(Red,Green,Yellow,Black) to a 4 different textbox's on vb.net project.
I am trying to set the class attribute of a list item on page load. Dim liItem As HtmlGenericControl = DirectCast(Page.FindControl("default"),HtmlGenericControl)liItem.Attributes.Add("class", "active")
This code doesn't work, not quite sure why.This is the error it is generating "NullReferenceException: Object reference not set to an instance of an object"
Is there a way I can assign a value to a class attribute using a constant? would like to do this so that I don't have tocode a constant value in the attribute and then again inside the class.
<TemplatePart(Name:=TESTVALUE, Type:=(GetType(ContentControl))>_ Public Class MyContentControl Inherits ContentControl
I have the following architecture for my project:UI -> Web Server -> App Server -> Database
I am using SOA architecture for my project. My Web Service is residing on AppServer having BL (Business Layer) / BO (Business Object) / DAL (Data Access Layer). I am exposing the BL using Web Service. I am getting the service reference to this Web Service at WebServer by creating the proxy using WSDL.exe. Now my question is:
I know that in a WebBrowser you can use Document.GetElementById to find an element by its name attribute, but I want to search the webpage for an element using the id or class atributes, how would it be possible to do this in a WebBrowser? I want to make it click on an image tag.
i am comfortable with class, namespace ,Sub ,Function ,Properties ...and so on. i studied about Custom Controls and Extension methods. There i found something new so called Attribute that are placed before classes and Functions definitions.[code...]
I've added an attribute for a user readable display name to my Enum values.However my code to convert from the user readable display name back to the Enum (function ToEnum) seems very convoluted.I am wondering if I am missing a better way of doing this (I am using Visual Studio 2010 with SP1.) [code]
I have a webbrowser control with a static HTML page in it, i wanted to loop through each of the DIV items, and look at the class attribute within them. When i run my test, the class attribute is always blank? I know they have a class attribute i checked in my HTML
I want a method of dealing with very, very, very big numbers (potentially a million digits). It is very cumbersome to deal with very big numbers in VB, would another language perhaps be better for that?
I have a main form which contains a few buttons...some of those buttons open up smaller forms...there is also a button for each of those smaller forms, which should let me bring the chosen form to the front and give it focus...basically like the tabs in your task bar let you switch between which program you are using...but I'm having trouble with this...I need to click the button 2 times before the form I want comes to the front...the first click removes focus from the currently activated form the second click then moves the form I want to the front.I need this to happen in one click..I[code] figured out the exact cause of the problem.it's due to the fact that the first click doesn't actually take effect since the child form has focus...so the first click actually just transfers focus to the main form...the second click does what it should.I knew it was going to be extremely obvious.so the question now becomes...how can I overcome this if that is possible at all...I know I've seen applications where I can still activate functions of the parent form in one click even if I have a child form open and focused.And it's basically what I need...it does what I want and lets me switch between child forms in one click...but it stuffs up the entire look of my parent form...the layout and colors get wacky...the transparency of certain things don't seem to work and my background image is gone..
Sometimes in my web applications I used to get this sort of error, I have no clue why is it coming however if I refresh the page few times the page is loading normally.I am using .net framework 2.0 and visual web developer 2005.
I have a simple class that I trying to populate from an XML document. The XML file has an attribute called TrackingID in the root node which I would like to get as a property. For some reason, when I deseralize the class, the TrackingID is null. Everything else populates fine. I have tried various attributes on the TrackingID property with no luck.
Write a program that makes change for amounts less than one dollar. Input to the program should be an integer less than 100. Output should be the original amount together with the proper set of coins that add up to that number. The program should produce change consisting of the minimum amount of coins possible. The output should be printed in such a way as to avoid unnecessary amounts.For example:
32 cents should be printed as:32 requires 1 quarter, 1 nickel, and 2 cents Rather than� 32 requires 1 quarter(s), 0 dime(s), 1 nickel(s), and 2 cent(s)
I had a strange problem editing a class in the property grid whereby the property grid would refresh incorrectly.I managed to reduce the problem down to a class with just two properties. I've included the code at the end to ease explanation.It basically boils down to a class with two properties. The first of which is expandable (a font)The class itself is expandable and also implements the CreateInstance method in the type converter.To see the problem, expand the font, edit, say 'Bold', and tab away. Two problems happen:
(1) The second property jumps up and ends up in the expanded font property.
(2) The '-' sign of the expanded font changes to a '+'.
The problem goes away by attaching ResfreshProperties(RefreshProperties.All) to the class. That's great, but I'd like to understand how it fixed the problem. I've had a look in reflector and can't find any examples of RefreshProperties being attached at the class level.
I'm trying to make a program that'll play the card game "War". I've started to code the dealing process, but it doesn't seem to be working. I currently have 3 comboboxes on the form each with numbers representing different cards, 1 that contains all the cards to be dealt, 1 that contains the user's cards, and 1 that contains the computer's cards. I plan to just draw random numbers from these comboboxes for the dealing. However, nothing happens when I click the tool-strip button that's supposed to deal the cards. [Code]
