Currently, whenever I pass a string to the db, if that string is empty, then i set that object to NULL by doing the following:
IIf(DescriptionTxt.Text.length > 0, DescriptionTxt.Text, DBNull.Value)
I was thinking about writing a function to reduce the length of this code, and make it more consistent.However, I was wondering, is there already a way of doing this in .NET 3.5?
I have a Javascript function for my select box, but after I included runat="server" to it, the script debugger highlights on this line below:
' for (i = 0; i < sourceTo.options.length; i++) { ' and says:
SCRIPT5007: Unable to get value of the property 'length': object is null or undefined
I included it because I wanted to loop through it in code behind and perform some other stuffs?
Code:
<select multiple size="8" style="width: 135px" runat="server" id="outletFromBox">
<option value="JP">Jurong Point</option>
<option value="IMM">IMM</option>
[code]...
[Code]...
By my logic, this should only assign .length to index IF the length of strItem is longer than 0. This check is there in case the listbox is empty, or the user has not selected an item. However, everytime I go through this code without an item selected I get:
[Code]...
I'm using FileHelper to generate object's property. Here is an example of one property:
<FieldOptional(), _
FieldTrim(TrimMode.Both)> _
<FieldNullValue(GetType(String), " ")> _
Public StoreNo As String
As you can see the StoreNo will either have a value or " ", one of the business policy is to check if the StoreNo is empty or nothing if the object's StoreNo is empty or null then the record will not create.
I though about creating an HasValue Function in the class to check the StoreNo and other properties in the object but I feel like it is a hack.
Public Function HasValue() As Boolean
Dim _HasValue As Boolean = True
If StringHelper.IsNullOrBlank(Me.StoreNo) Then
[Code]....
I don't think this approach is an ideal solution. what if the StoreNo is remove or change to something else. What's the best approach to check object's property?
CustomerStreamToRead' is used before it has been assigned a value. A null reference exception could result at runtime.I get that warning once I commented out the streamreader line listed below. The warning shows for the line loading settings(z). The app runs but I don't like warnings in my error list.
Code:
Public Sub LoadSettings()
Dim Z As Integer
Dim CustomerStreamToRead As StreamReader
[code]....
Lets say I have two tables:
Parent
PK
ParentID[code]....
These tables have a relationship where the Parent can have 0 to many Children.I wrote this query "Select * from Parent left outer join Children on Parent.ParentID = Children.ParentID", thus returning all Parents regardless of whether they have children.This would return something like this if run directly against the database:
ParentID
FirstName
LastName[code]....
Now what I would like to do is use the ExecuteQuery method on my LINQ data context to run this query and return the set of objects related to it.What I am expecting to happen is have LINQ return two Parent objects one (Joe Smith) with one child in its Children collection and one (Tina Jones) with nothing in the Children collection.However what I am getting is an exception stating "The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type.I am assuming, since the error message is not very descriptive, that it is talking about the fact the ChildID is an integer and is not nullable and cannot correctly generate a Children object with that value.
Variable 'loNode' is used before it has been assigned a value. A null reference exception could result at runtime.
why I am getting this error?
Imports System.Xml
Module Module1
Sub Main()
Dim doc As New XmlDocument
[code].....
I have a class and method exposed to a client asp.net app. The class looks like
<DataContract()> _
Public Class Class1
Private v_string As String
Private v_integer As Integer
[code]....
The method is declared as
<OperationContract()> _
Function GetStuff(ByVal bar As Class1) As String
In the client code I create an instance of Class1 and set the values for v_string and v_integer, but using Wireshark to look at the xml being sent to the server only a value for v_string is being sent as part of Class1. I'm guessing this is because it considers the value of v_integer to be null/not set. Here is an example of the client code.
Dim MyService as New Service1.ServiceClient
Dim test as New Service1.Class1
test.P_integer = 1
[code]....
how different types are passed/used since Integer is a intergral type and String is a class, but can't seem to work out what to do to fix the problem.
this is not working?
[Code]...
End WhileI am trying to read from the ": " to the end of the line. I keep getting this error: Index and length must refer to a location within the string. Parameter name: length
am getting the above exception while swaping Items in the list(lstRoutePriority).PFB my code
if (lstRoutePriority.SelectedIndex > 0)
{
//Swap the two items
[Code].....
I have some code which gets child items for a menu via the GetChildren function which takes a list of menuData: Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
If menuData.Children IsNot Nothing Then
menuData.Children.AddRange(GetChildren(menuData))
End If
Next
If I check if menudata.children isnot nothing, it always is nothing because the GetChildren function is yet to run (providing the child items, which do exist). If I remove this check and just have this code:
Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
menuData.Children.AddRange(GetChildren(menuData))
Next
Then I am presented with a Object reference not set to an instance of an object error on menuData.Children.AddRange(GetChildren(menuData))
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.
This is related to my last question.Even though Access considers Nulls and zero-length strings (ZLS) separate values, often developers wish to treat them as equivalent for the sake of an If...Then statement or some other stretch of code. One way to accomplish this is to write code like this:
' Not so efficient
If IsNull(varAge) or varAge = "" Then
' do something
[code].....
I'm working on a small project, and ran into an issue. I'm creating new picture boxes on a form to represent a control. My question is how would I code a click event for an object that isn't on the forum initially? Also, how can I keep track of which object is assigned to which data in an array? (IE picturebox 0 is array(0) of data)
View 7 RepliesI have a Job Register Table and that table doesn't have any records.
This is my LINQ code:
Dim QRecordCount = (From LC In CntxtJobDetails.JobRegistrations _
Where LC.JobCode <> 0 _
[code].....
When i execute this linq to sql command its given an error "The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type." 0 Records in my Commotidy Table
I want generate manual number and get the last CommodityCode.My Code as follow,
Dim QRecordCount = From RC In cntxtCommodity.CommodityMasters _
Where RC.CommodityCode <> 0 _
Select RC.CommodityCode[code].....
"Index and length must refer to a location within the string. Parameter name: length" whenever I run this code
[Code]...
If using the following in an if statement I get an error: If trg.Name.Substring(4, 6).ToUpper <> ("ABCDEF") Then I get the error: "Index and length must refer to a location within the string. Parameter name: length"
I assume this is because the string (trg.name) is too small for the 4, 6 substring. What would be the correct method of working around this problem? VB.net Studio 2008.
This code works well but somehow it is giving me a warning saying: "Variable 'str1' is used before it has been assigned a value. A null reference exception could result at runtime."How can I remove the warning.
Public Shared Function getAllColumnNames(ByVal tblname As String) As String()
Dim com As New OleDbCommand
Dim con As OleDbConnection
Dim str1() As String
Dim dtable1 As DataTable
[Code] .....
I am making use of a 3rd party dll and am encountering some strange behavior in VB, which doesn't occur in C# Perhaps someone can explain what is going on. Anyhow, I am making use of a method in this 3rd party library which accepts an array parameter ByRef. The end result is the variable should remain null after the method call, but it is returning initialized for some reason.
[Code]...
Currently working on the status bar for application. I would like the status bar to display message errors if a user makes an invalid entry. I have a module which contains the main procedure and procedures to change the text property of my status bar. A Call is made to the procedures from one of the forms that requires the user input. The application compliles but I get an unhandled exception of type 'System.Null ReferenceException' Object reference not set to an instance of an object. [Code]
View 4 RepliesI have 26 buttons, each corresponding to the letter of the alphabet from A thru Z. I have a method that I've created that accepts a button as a parameter and sets the case to UPPER case if the text of the button is lower case or lower case if the text of the button is UPPER case. My method looks as follows:
Private Sub ChangeLetterCase(ByRef MyButton As Button)
If _upperCase Then
MyButton.Text = Chr(Asc(MyButton.Text) + 26)
[code]....
when i transfer the bytes sent by the client program to a string the string length is affected.when i put the bytes sent by the client program to a message box. it returns the corrrect text. but when i check the length it will return 8192 or higher. but the actual size is just 5.
My Code
Dim tcpClient As TcpClient = tcpListener.AcceptTcpClient()
RichTextBox1.Text = RichTextBox1.Text & vbNewLine & "Connection accepted."
' Get the stream[code]....
I have a long string like this
dim LongString as String = "123abc456def789ghi"
And I want to split it into a string array. Each element of the array should be in 3 characters length[code]...
I'm writing some code that takes a report from the mainframe and converts it to a spreadsheet. They can't edit the code on the MF to give me a delimited file, so I'm stuck dealing with it as fixed width. It's working okay now, but I need to get it more stable before I release it for testing. My problem is that in any given line of data, say it could have three columns of numbers, each five chars wide at positions 10, 16, and 22. If on this one particular row, there's no data for the last two cols, it won't be padded with spaces; rather, the length of the string will be only 14. So, I can't just blindly have
[Code]...
If I have a string Metal is hot : Metal length is 5 cm ; Metal is red. I want to get the sub string that is talking about length: hence I want to extract "Metal length is 5 cm".
[Code]...
[Code]...
I want to create a ProgressBar with my array length, whithout timer object. When ProgressBar increment, the value in array appears in a label.
Is there simple way to SyncLock an object that can be null? And before you ask for it, yes, I know that it isn't logical to perform a SyncLock on a null variable. However, that would simplify my code because right now, I have no choice but to perform a null check all over the place before calling a SyncLock.
[Code]...
I just want to check and see if this object is null. if i do not and it is my applications closes.I have also looked into a null reference exception. I will do whatever as long as it handles "null".[code]
View 2 RepliesIf I have a variable, X, of type SqlDecimal, that was instantiated without providing a decimal value parameter to the constructor, then the .IsNull property is True: Dim X As New SqlDecimal '.Value = Null..If I have a Stored Procedure that acepts a single parameter, @SqlDecimalParameter, of type Decimal, the value of this this parameter could be NULL or a decimal value. This is how I would normally call the stored procedure:[code]It seems like the 1st example should work. Am I missing something? after all, the Sql datatypes are designed to work with SQL Server, I thought.[code]I get the following error:Failed to convert parameter value from a SqlDecimal to a Decimal.It works when X.IsNull is True.How do you set the value of the PARAM object when it can be NULL?
View 1 Replies