I have a form where when the user clicks the button the values of the form are stored in SQL database. I want to write code in order to check if a specific textbox-value already exist in the database table (in the field "Name"). I 've tried writing something but it doesn't work properly.
View 2 RepliesIf Double.Parse(list_numbers.Item(i), possibledouble)
list_numbers is a list of strings
list_numbers.Item(i) = "0.000"
possibledouble is a double
debugger returns "input string was not in a correct format"
i thought that the double parse would convert the string into a double format of "0.0" but it gives me an error.
Iam 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 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.
Im trying to check to see if a value of a label changes over time. however I can't seem to get it right.
dim val1 as string
dim val2 as string
private sub form1_load()
dim val1 = label1.text
end sub
[Code]...
problem is it will only check it once after ten seconds when the timer is set to 10 seconds i need to to check it every 10 seconds becuase these values display altitude, and if the server freezes the altitudes dont change. I need to make sure they are updated and not frozen.
am new to VB.NET and i was wondering if anyone here knows how to check for duplicate values in strings?
View 11 RepliesHow I could go about checking a typed value in a combo to the values in the combo box. I am making a system to select lockerID and Supplier ID I want the user to be able to enter the value in the combo box as well as select the value form the list in the combo box. Here is the code I have been trying.
If cboStockID.Text = "" And cboStockID.Text <> cboStockID.Items.ToString Then
MsgBox("Please enter Stock ID")
Exit Sub
ElseIf cboSupplierID.Text = "" Then
MsgBox("Please Enter Supplier ID")
Exit Sub
End If
I'm basically putting some validation logic around an undo button on my form and i'd like to check whether any fields on the form have had their values changed so i can ask the question "abandon changes?". This seems like something pretty standard to me but I can not see how to check whether a value has had its contents changed (without recording a before value and comparing it to the after value which for large forms would be quite horrendous to code).
In the language i used to use we used to walk the object tree (so we dont have to specify each object individually like text box, combo box etc) and check any object that have value-changed = yes to indicate the validation was required.
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 have a form where two fields on the first page of the form make up the primary key. I want to check for duplicate values before attempting to insert the record, since I don't want the user to go all the way through the form only to find out they can't submit it. So I'm trying to check for duplicate values when the user tries to go to the next page of the form. I wasn't quite sure how to do it, and sure enough I'm getting an error. ("Object reference not set to an instance of an object.") The problem is apparently in my if statement, "If myValue.Length > 0 Then", but I'm not sure what needs to be in place of that.
Protected Sub CustomValidator1_ServerValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles CustomValidator1.ServerValidate
'get values
[code].....
I have declared a class in VB.NET using VS2K5 with some shared variables and made that class a dllI made use of that dll in another project and tried to make use of those variables. Even though I can able to make use of them, Im unable to view the values of those variables like the values of normal variables when Im debugging. Is there any way that I can watch the values of those shared variables during debugging.
View 1 RepliesI 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 have this string in vb.net. let me know how I can enclose the values in double quotes
dim str as string=""str.Append("EmpID=" & empNo & " DeptID=" & deptID & "")
I want the value of string to be EmiID="10" DeptID="20"
can let me know how I can enclose the values in double quotes
dim str as string=""
str.Append("EmpID=" & empNo & " DeptID=" & deptID & "")
Im having an issue with a certain query,Dim nwLat As Double Dim Ssql As String
nwLat = nwLatHidden.Value
Ssql = " select * from customer where latitude < " & nwLat
TFRcount.SelectCommand = Ssql
TFRcount.SelectParameters.Clear()
TFRcount.DataBind()
All it does is refresh the page and does nothing; it should populate a chart. However when I replace nwLat with a value (eg where latitude = 56) it works perfectly and populates the chart. Any ideas what's wrong with nwLat?
EDIT: I switched nwLat to long and it works; however it only takes the number up to the decimal and ignores the rest. Any way to fix? (eg as double 56.764746 and long 56)
how do i generate random double values between range, for example:value between 2.50 to 3.50?
View 7 RepliesI'm working on a vb.net application which imports from an Excel spreadsheet.
If rdr.HasRows Then
Do While rdr.Read()
If rdr.GetValue(0).Equals(System.DBNull.Value) Then
[Code]....
But when passing the value to the SQL insert I get: "Nullable object must have a value."
Solution:
Fixed by changing the datatype of the parameter in the sub I was calling and then using Variable.HasValue to do the conditional DBNull insert.
Basically I have a form which has 2 drop downs. In the 1st drop down I am selecting City category. When the city is selected I want to update the 2nd drop down values in correspondence to 1st value choosen in 1st drop down. I have done like this,This adds the value in the 1st Drop Down:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim s As String = "connection String"
sqlconn = New SqlConnection(s)
[code]....
I've never really used the Check List Box in the past, however, for the recent program I am developing, I am using this control rather than individual check boxes scattered across the form.Anyway, I want to be able to program through code which items get checked in this checked list box. Specifically, I have a variable that contains the text of each check box that I want checked.With a normal check box, I can simply say:
Dim strNames As String
strNames = "John Doe, Mark Johnson, Mike Brown, Cindy Smith"
If strNames.ToString.Contains("Mike Brown") Then[code]....
I am building VB.NET application that takes data from text files that are exported from a legacy DOS program. These are written to a datatable and displayed in a datagridview. Right now my code simply loops through the datagridview and inserts the data into the database (SQL Server). There is a requirement now that the client number must be checked before the insert to see if it exists in the database. If it does, then the value of one field (tax rate) is checked against the value of the field in the datagridview. If there is a difference, then the rate is to be updated in the database and the data that was in the database is to be written to a history table for audit purposes. If the client number is not there, then we are to do the insert (which is already written). I want to know what is the most elegant and efficient solution for this problem.
I need to compare what is in the database table with what is in the datagridview, update the history table for records that exist, and then insert new records.
Is there such a thing as a type similar to a point, but contains a pair of decimals, or a pair of doubles, rather than integers? I searched the forums and google with no luck. I can't believe this has never come up before, I must have been using the wrong search terms.
View 4 RepliesI am attempting to read a series of double prcision float values (x,y,z coordinates) from a binary file using the binary reader. Everything works fine except that when I read the number back it is different then the number that was written there (original file is generated by mining application).
written number : 78897.6476586
file contents hex : 40 F3 43 1A 5C CF 43 A4 this converts back to the same number as written using a IEE 754 conversion program. VB returned value : -5.45100266729248E-134 using .readDouble()
I have tried to step thru the file in one byte steps to make sure that I have the proper start position but that did not help any.
i have 3 textboxes and 3 columns in listview like names ProductCode, ProductName and Price. i save the textbox values to Listview columns.Now i want to that when i double click on any row in listview these values will be editable in the textboxes again for edit mod.
View 1 RepliesIn the discussion in this thread: [URL] it was reveiled to me that vb.net, using double, could only calculate values up to 18 digits after decimal.... so I started thinking and came up with this class
Public Class LargeNumber
Private pNumber As String
Public Sub New()
[CODE].............
I want to split the string into a series of doubles.... and than combine them into a large number.... The size of each double component should be 18 digits on a 32 bit computer... so that I will have room to add the last carrier...
I am using the following code to create an array consisting of double values specified by start stop and step. The problem with that is that for some weird reason there is a calculation error that seems to originate from the for statement causing the values to drift after the 11th to 12th digit after the comma which is quite irritating for the purpose i am using it.
[Code]...
Whenever I store values to a double-type variable, and ask to display it on the screen, there seems to always be a discrepancy, for example, I entered 7.416 to a textbox and assigned it to a double. When i ask for it to be displayed, it used to be that the 7.416 is returned to me. But just a few days ago, when I debugged my program again, it returns numbers like 7.4159987.......[code]....
View 7 RepliesSo I'm writing the equality operator overload (Operator =())for a custom object, and the resulting mess of If conditionals is just an eyesore. But so far, it seems like the only sane way to check the values to as to match the specific behavior of this object.
The rules are:Num1 is required, period, and both the left and right operands and must be equal for True. Else, False.Num2 is optional, but if specified, must be present for both the left and right operands, and must be equal for True. Else, False.Num3 is optional, but can only be specified if Num2 is also present. Else, False.Num3, if specified, must be present for both the left and right operands, and must be equal for True. Else, False.
[Code]..
I also know that I could cache elements of the checks into booleans and then use those to reduce the amount of text. But that seems like a waste of cycles just for code readability. So I wanted to know if the SO community had better thoughts on reorganizing it, just in case I'm being too verbose with my checks.