I have a DataGridView1 populated by sql searches. On the rare occasion that nothing is returned, my app cannot make use of data so I'm trying to check for null values. My code below is not correct because IsDBNull is not a member of the of the DataGridView1.
If DataGridView1.SelectedRows(0).IsDBNull Then
MsgBox("Nothing to display")
Exit Sub
End If
I want to check if two combobox values are equal. The comboboxes are in a datagridview.I found you need to use datagridview_EditingControlShowing to add a handler to the comobo boxes for selectedindexchanged. I can do this with this code.
Code:
Private Sub dgridRegisters_EditingControlShowing(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewEditingControlShowingEventArgs) Handles dgridRegisters.EditingControlShowing
Dim combo As ComboBox = CType(e.Control, ComboBox)
[code]....
However, the message box comes up for every combobox in my datagrid when I change the index, not just the cmbPort2. I would like to have something like this...
If cmbPort1.selectedindex == cmbport2.selectedindex then
'do something
endif
..but it doesn't seem possible.
I need to check if a value from a date column is equal to null. I can't find how to do it.
Wat I got now is:
if ds.tblBooking(row).CancelledOn.compareTo(dbnull.value) = true then
But this doesn't seem to work, I think it's because I'm using a strongly typed database.
I have a fairly simple piece of code:
Private _PurchaseDelivery as PurchaseDelivery
Protected Overrides Sub InsertItem(ByVal index As Integer, ByVal item As PurchaseDeliveryItem)
[Code]....
Which is inside a class which overrides a custom list base. The code is occassionaly throwing an unhandled exception, System.NullReferenceException, on this line when used in production:
If _PurchaseDelivery IsNot Nothing AndAlso _PurchaseDelivery.DefaultSKUBinID.HasValue Then
DeafultSKUBinID is declared as an Integer? (Nullable Int) in the PurchaseDelivery class. I cannot see what might be causing this error, why would this be returning an error?
I have tried to solve this myself and I know I am probably doing something really silly here what I have is two different registry values that control what is displayed in the combobox on my form RegistryKey1 has the following values:0,1 or it does not existRegistryKey2 has the following values2,3, or 4 the combobox has the following values 0,1,2,3 However here is the problem if the RegistryKey2 is 2 then it further has to be checked if RegistryKey1 is either 0,1 or does not exist
if it is 1 then the selectedindex = 0
if it is 0 or does not exist then the selectedindex = 1
if RegistryKey2 is 3 then the selectedindex = 2
[code].....
as title says. and if it has the same values, delete one of them and add (2)
so itll be like: - before the filter:
[Code]....
i m trying to run a query on an MSAccess table, but it does not give me any count but only 0.
There are 3 null values which i should be getting but it does not give me the result. This query works perfectly in MSSql Server 2008.
the query is :
Quote:
SELECT COUNT(*) AS Cntr
FROM (Modul m LEFT OUTER JOIN
Relation r ON m.Mod_Name = r.von)
WHERE (m.[group] = '')
I need a workaround for this but am unable to find one.
checking im my textbox contains null valuefor example i have ten textbox how do i know if a textbox has no text in it?then gotfocus to that specific textbox?
View 3 RepliesI'm using Visual Basic .NET to work with a USB HID device.Most of the time, I can receive data from it perfectly... but one out of every thousand transfers or so, my code will think it has received data when it actually hasn't.The device writes to an array of bytes. I wanted to check to see if the received packet is empty, by doing something like this:
If myDevice.dataPacket(1) <> Nothing then
myDevice.rxDataReady = False
[code].....
ve a simple vb code similar to the below,
Function getvalue (ByVal Val as double) As string
Dim Num as Integer
Dim Prd as double
[code].....
Is there anyway to check for a null here before it reaches this part of the code? tmpLabelData(0) = m_node.Item("CONTAINER_NAME").InnerText. Some XML has it while others do not. I cant seem to find a nice way to handle a null on these?
View 1 RepliesI'm querying a SQL DB and sometimes the result is Null, so I thought I would test this but my code results in an error "Data is Null. This method or property cannot be called on Null values."
Here is a snipet of my code:
For i = 5 To 6
cmd = New MySqlCommand(query2t & i, db)
rdr = cmd.ExecuteReader()
rdr.Read()
If Not IsDBNull(rdr.GetUInt32(0)) Then
[Code] ......
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.
i am working in windows appl vb.net 08. And i am working in Access DataBase.I have one Table Called "Person" . In this "Person" Table one Column Name Called "OtherName". In this Column binded in one of the Combobox in a Form.But the Problem is "OtherName" Column having the Null Values.Before i bind this Column to Combobox i want to convert this NULL Values to String. Why i need the values in STRING means , In my code i using this Combobox as a filter in SQL Query.If i didn`t change the Null Value to STRING , The Combobox SelectedText or SelectedValue is Showing Nothing. So i am not able to get the Record.
Whn i write a Sql Query to Combobox and apply filter in WHERE statement like Combobox.Selectedtext or Combobox.SelectedValue In "Selected Change Committed Event" then i should get the record in the Output right but unfortunatly i am not getting the Record. The Record Count in DebugPrint showing 0.
[Code]...
I have a module and form. Module has a structure.
[Code]...
Actually values are not stored in that array list permanently. its storing temporarily and then destroying. i want to store that values in that arraylist permanently.
I have an ASP.NET application that crashes when a null date value is returned.
The code line is:
excelWorksheet.Cells("A" & xlRowCounter).Value = IIf(IsDBNull(dRow("sysdate")), "", Format(dRow("sysdate"), "MM/dd/yyyy"))
Error message:
ERROR: System.ArgumentException: Argument 'Expression' is not a valid value.
How would I check for a null date, and replace it with "" in my app ?
I keep getting the error "Object reference not set to an instance of an Object" on the below highlighted line of code and I understand why. It's because I'm checking for something that hasn't even been initialized yet. My question is, what's the best way to check a DataTables row count without getting that error before refilling it?
If Not ds.Tables("tblNotes").Rows(0).IsNull(0) Then
ds.Tables("tblNotes").Rows.Clear()
End If
adp.Fill(ds, "tblNotes")
I'm working with a database application and i want to check if there is a null value in a specific column but it works only when its not null but if its null it throws an exception automatically. I tried to change the null value property of this column but I'm not able it shows a message that its not a valid property. I tried to change the source code in the code editor but it changes back automatically. Is there a way that I can work around this?
View 5 RepliesI am trying to write a generic function that will check each database parameter to see if it is null, and if so, return DBNull; if not, return the object.So here is my function:
Public Shared Function CheckForNull(ByVal obj As Object) As Object
If obj <> Nothing Then Return obj Else Return DBNull.Value
End Function
[code].....
I constantly find myself having to do code similar to the following.[code]Is there anyway to check for both on a single line? When i'm checking a condition for a great number of answers, I sometimes end up with conditionals 6-sets deep. If i check for null first, an error still pops up, even though VB shouldn't check since the first condition failed. i.e.[code]
View 8 Replieshow to check null excel worksheet?
View 2 RepliesI'm implementing a State Machine in WF 4.0. In some transitions, I have added a condition where I check that some variables have the expected values. The variables are enums and booleans, and everything is fine.
However, now I tried to evaluate when a property is null. I have and argument in my workflow, let's say, 'MyArgument'. In a transition, I try to put a condition like 'MyArgument.MyProperty = Nothing'. I never developed in VB.NET, I don't know if I'm missing something here...
VS2010 gives the following error: "Error 4 Compiler error(s) encountered processing expression "MyArg.MyProp = Nothing".
Operator '=' is not defined for types 'XXXX' and 'XXXX'
The type names are exactly the same, and I have debugged VS2010 to ensure that my assembly is not loaded from 2 different locations.
How can I check if the property is null or not?
BTW, I'm using VS2010 SP 1, with .NET Platform Update 1 installed, on W7 64 bits.
I am trying to implement a function for my SSRS report which will return a color value depending on the values of three dates.
[Code]...
I am using following code in rowdatabound fn.
Protected Sub gvwMileStone_RowDataBound(ByVal sender As System.Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs)
[code]...
ddlEProjectLevels is dropdownlist in edititemtemplate.Whwn i click edit in 1st row ddlEProjectLevels gets loaded with data from database.But in 2nd row dropdownlist does not contain values.Again in 3rd it gets loaded from db.Means in alternate rows,when i click edit dropdownlist(ddlEProjectLevels) doesnot load values.Can anybody help?
like to be able to add up (and insert) all the values of a column in the datagridview but can't work out how to do it.I would like to insert a value into the ApplicantID column and read a value entered in the Grade column when a button is clicked
View 5 RepliesI have a DataGridView on a WinForm that has a column with a combo box in it. The combo is populated from a datasource and all works great. My problem is this: How do I get the value selected (or the text) in the combobox for a specific row when a button is pressed?
View 3 RepliesIam trying to Check Values Of 2 textboxex .. n then Print A certain Amount.
[Code]...
I'm trying to make a small program that helps cashiers to practice typing barcode on their machine. Barcode consists 12 numbers, and it can start with 0. Below are the code I worked on so far.
[Code]...
I have 14 values, that change constantly. I need to know how to check each value against each other to see if they are within 250 of each other. [code] I want these two values in the listbox to blink red in the list box. but i always want each value to check every value in the list box. i dont even know where to start short of programming each possibilty with a if than statement and that would take forever
View 1 RepliesI need to get all the different values from my dgv, but no duplicates, and add them as rows to my dataset.for example if my dgv col1 have the following values:
a
b
c
[code]....
the procedure must get the values from dgv1 and add it to a dataset if the values isnt already there.My dataset should have this:
a
b
c
d
e
