[Code] Now the problem is that after i put this user-control in a form, I have to set a value for the Handled file. Otherwise it gives me a value cannot be null exception. Is there a way that i can set code that would execute in the case of the value being null? [Code]
View 14 RepliesI'm using some VB.Net code to manipulate files on my system - the idea is that the code checks if a file exists, and based on a value read from a text file elsewhere the system decides what to do... For this I'm using a 'select... case' statement to decide on the action to take. However, when assigning a value to the variable, the code doesn't even find the option to go for... Here's the VB code:
[Code]...
If you assign a value to a nullable integer via a ternary operator, it can't become null..While this question may seem like a duplicate of many, it is actually being asked for a specific reason.Take this code, for example: Dim n As Integer? = If(True, Nothing, 1) In that code, the ternary expression should be returning Nothing, but it's setting n to 0. If this were C#, I could say default(int?) and it would work perfectly. Now it looks like I am going to have to ditch the ternary and use a regular If block, but I really want to use the ternary. If Nothing were truly VB.NET's equivalent to C#'s default, how can you explain this behavior?
View 1 RepliesI have a date time picker bould to a Nullable Datetime field in a sql server datatable. The ShowCheckBox option is set to true. If the user unchecks the checkbox on the datetimepicker I would like to the field to be set back to null in the DataTable. The default behaveour does not seem to do this and there is no specific event for the uncheck.
Private Sub dtpCertDate_ValueChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles dtpCertDate.ValueChanged
If dtpCertDate.Focused Then
[code].....
I am working through my new MVC book and of course, the samples are all in c# as usual. There is a line of code that says public bool? WillAttend { get; set; }
The author explains that the question mark indicates that this is a nullable (tri-state) bool that can be true, false. or null. (A new C# 3 convention.) Does vb.net support any convention like this. Certainly I can declare a boolean in vb.net and I can explicitly set it to Null (Nothing in vb.net).
I am creating a setup project for my VB application. Everything seems to look fine. However when I tell it to build the solution I get the following error:Property 'keycode' is non-nullable. I have never seen this before in other setup projects and I can't find any help from MS.
View 8 RepliesIn the below sample code, I have tried to use Nullable(of T) for DateTime and I want to use it same of the Dimensions property which is List(of Dimension).
CODE:
Apparently this used to be a way in VB6 and VBA to short circuit and execute the first true case:
[Code]...
until i put in On Error Resume Next i was getting runtime error 94 in vaild use of null
i would like to have something like case null: Result = " Unknown"
Function GetPingStatus(ByVal StatusCode As Long)
On Error Resume Next
[code].....
I was under the impression that any time I set a Nullable(Of Something) to Nothing, it will take the value of Nothing.In a class, I have;
Private _something As Nullable(Of Double)
Public Property Something() As Nullable(Of Double)
Get
Return _something
End Get
[Code]...
In my page, using this class I set Something = Nothing, but as I step into the Set method, value = 0.0.Am I doing something wrong here? Or do I just not understand Nullable types yet?
I have Nullable properties in my class:Public Property FileStatusID() As Integer?
Get
Return m_FileStatusID
End Get
[code].....
I tried to build my project but it has 1 build error
:Property 'Keycode' is non-nullable.
I double click it but it points nowhere. I'm really desperate. My project consists of Crystal Report. It had just been upgraded from version 8.5 to version 11. Is it possible that this is the source of error?
This function loops all properties of an object to create the updatequery to save te object to the DB.
We had to make some changes to it because of the introduction of nullable properties. If the property is nullable we would like to check the 'HasValue' property. This does works when it has a value. When the property has no value we get an 'Non-static method requires a target'-error at the CBool-line
An other way to check the 'HasValue'-prop of a property using reflection?
Private Function GetUpdateQuery(ByVal obj As Object, ByRef params As List(Of SqlParameter), Optional ByVal excl As String() = Nothing) As String
Dim sql As String = String.Empty
[Code].....
How to set Nullable Property in vb.net like "public decimal? unitprice {get; set;}"
View 2 RepliesI have a nullable public property on a class using Vb.net 3.5:
Public Property TicketCharge() As Nullable(Of Decimal)
Get
If _TicketCharge = Nothing Then
[code]....
I'm trying to use a select case statement to evaluate the value being passed from an array list...any suggegstions. I need to determine if the array is null or not, and setup my select case statement based on if the array is populated. See sample code below Code Sample selected As New ArrayList
Dim dvExisting as DataView
Dim grdExisting as DataGrid
For
i = 0 To dvExisting.Count - 1
If grdExisting.IsSelected(i) Then
[Code]...
I have written a .Net 4.0 Winforms Numeric Editor control (which inherits from TextBox), and I have added a Value property that is a nullable decimal type, as follows:
Public Class NumericEditor
Inherits TextBox
Private _value As Decimal? = Nothing
[code]....
how to get around this exception, particularly when I'm databinding a number field to a number property, and there should be no string conversion happening. (To further complicate things, I'm using a similar technique for another control where I databind a DateTime field to a nullable DateTime property, and that control works just fine.)
I 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].....
I want to retrieve total value from sales table in sqlcommand object. Below is my sample code.I will get error if there was no data in the tabel that matched my query saying that null could not be converted into decimal.
I would not get error if there was data that matched my query and returned the total value in tmpSales variable.My question is what is the best way to deal with this situation?
Dim CmdTmp As System.Data.SqlClient.SqlCommand
Dim tmpSales As Decimal
CmdSales = New System.Data.SqlClient.SqlCommand("SELECT SUM(Total) FROM Sales WHERE Date>= '1 Jan 2011' And Date<= '30 Jan 2011", ConDB)tmpSales = CmdSales.ExecuteScalar
I have some code to execute code at runtime...
Here is the main
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Try
If TextBox1.Text.Trim <> "" Then
If TextBox2.Text.Trim <> "" Then
[code]....
When the button is pressed, it all works and the following files are created: yahoo.dll and yahoo.pdb My question is this: What is the code to load the already compiled yahoo files to execute the code again, without having to recompile the code?
I have the following POCO:
Public Class T1
<Required()>
<MaxLength(128)>
<Key(), Column(Order:=0)>
Property K1 As String
[Code]...
I would expect C2 to be created as Nullable, but both C1 and C2 are Not Null. Adding
<Required(AllowEmptyStrings:=True)>
Does not make a difference, as it seems the decoration is aimed at data validation, not DB creation.
So how do i get a nullable column with Code First?
I am trying to create a settings class.The Property Test() is a list of strings.When I add a string such as: t.test.Add("asasasAAAAA")I want it to autmatically turn lowercase. using t.test.Add(("asasasAAAAA").ToLower) will not work for what I need. [code]
View 2 RepliesSo I'm building an application that is going to do a ton of code generation with both C# and VB output (depending on project settings). I've got a CodeTemplateEngine, with two derived classes VBTemplateEngine and CSharpTemplateEngine. This question regards creating the property signatures based on columns in a database table. Using the IDataReader's GetSchemaTable method I gather the CLR type of the column, such as "System.Int32", and whether it IsNullable. However, I'd like to keep the code simple, and instead of having a property that looks like:
[Code]...
Public Class Customer
Private m_CID As Integer
Private m_FirstName As String
[Code].....
My question is that do I need to add an OID in customer class or I can directly send a query to customer table when ever an order is made.
'Attributes
For Each attRefID As ObjectId In myBRef.AttributeCollection
Dim myAttRef As AttributeReference = attRefID.GetObject(OpenMode.ForRead)
[Code].....
How do I tell if my Enumerator property hasn't been given a value?
How do I tell if it is blank?
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?
on a Windows Form, an object myObject is bound to myObjectDataBindingSource like this:myObjectDataBindingSource .DatSource = myObject on the form, i have a check box bound to the property: chkProp1 for example of the object: myObjectDataBindingSource In the code when the checkbox is clicked, I need to go in code and change another text property of the object txtProper2 for example like this:
Private Sub chkProp1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkProp1.CheckedChanged
[code].....
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]...
I want to execute a code after every 5 min.I am trying to develop the application in .net and using the C# as a backend language.My basic requirement is a C# code which executes after every 5min which i click a start button on my .net form.
View 6 Replies