I'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.
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 Repliesi have an array of booleans whose current boolean values I want to preserve but add additional length to the array? How can I achieve that? My code looks like this:
Dim Array() As Boolean
Dim ArrayInterimShort() As Boolean
ReDim Array(119)
[code]....
Straightforward question: I have a few variables that are doubles. I would like to be able to store a "null" state in them, i.e. I need to be able to represent that the variable doesn't contain valid data. I'd really rather not associate a boolean "is valid" variable with every single double
View 2 RepliesSo I have a class made in c++ and need to convert it into vb.net but I got problem converting a certain part of a function. [Code] What type of variable is "double&", I know a double but what's with the "&"? It isn't " double &dec_deg" so it isn't an address (pointers etc.)? and how would i convert that to vb.net?
View 5 RepliesWhen the clear button is clicked on my interface I need my variables that are set as doubles to clear...I tried setting them to zero but that messed up my equations and caused more problems. Is there some method in double that clears them out or sets it back to nothing.here's the coding
'button i need to clear my textboxs and variables
Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
[code]....
im having a simple computation problem here....
[Code]....
I've came across to quite an unusual problem with dividing integers with double variable. I've created For loop where to sum-integer interval -double is added. When sum reaches certain number text is displayed as showed below:
[Code]...
If i have a variable '12'
and a variable 'hello'
how can i double the '12' each time the variable is used?
What im trying to do is have a textbox which the user writes in a number, the number they enter then determines the amount of times a variable is written in a textbox.
so if the user were to put '3' into the textbox and click go, it would print hello12hello12hello12, how can i increase the number 12?
what i want it to do is look like this when the user presses go: hello12hello24hello36
Datatable contain some values like 0.0,10000.00,54678.94. I am getting that values using for loop and store it in a variable in double datatype. I want to add these nos and store it in a variable. Each time variable value changed.
for loop
Dim ds5 As dataset1.pro_dtsumDataTable = TA5.GetData(TextBox1.Text, users)
If (ds5.Rows.Count > 0) Then
Dim y As Double
y = Double.Parse(ds5(0)("sum(fld_primary)").ToString())
Dim y1 As Double
y1 = 0 + y
End If
Next
First time y1=0.0
Next time the value of y1 is not added to previous value.
I want the result y1=64679.34
I'm currently working on an assignment for university and I could really use a hand.I need to plot the equation y=0.2*sqrt(1-(0.25/x)^2)
View 5 RepliesI need to truncate to sertain amount of decimals for example : dim x as double;x= 6.98455 textbox1.text = x that mean textbox1.text= 6.98455 I need textbox1.text= 6.99
View 4 RepliesI want to see if a variable's type is string or double type. How to do it in vb.net immediate window?
View 1 RepliesI have a double value like 3768.595863. if i round this value then i will get 3768.596 but i want 3768.595.how can i get that?please reply.
View 7 RepliesHow do I define a variable which holds double quotes. when I try to define the variable like this [code]...
View 2 RepliesHow to put data containing double-quotes in string variable? Aug 01, 2003 02:30 AM | LINK I need to store a string that contains words in double quotes. The complete string data is presented to the variable in double quotes, but the next double quotes within the data ends the string and the remaining text gives a syntax error. How can I place literal double-quotes in a string variable? For example:
[Code]...
How can I assign a variable which may contain a null value to a variable which is declared as Dim var1 as String and then use that variable to insert into access database table?
View 3 RepliesI'm using some session variables to store and pass data across several pages of an ASP.Net application. The behavior is a bit unpredictable though. [Code] Ok so far so good, on a normal page load. If the user completes the form action, hits the next page, and decides OH NO, i needed to change field xyz, and clicks back, corrects the data, then submits, the session variable is showing as NULL. Why would a cached session behave this way? I'm not destroying/clearing the variable, unless I fail to understand the scope of session variables.
View 1 RepliesHow can I get access in a fast way to the single bytes that form a double variable?
In pseudo-code I want to do something like this:
Dim myDouble as Double
Dim myArray(7) as Byte
myArray = myDouble
'continue doing things with the single bytes
The code is meant for use in a I/O-handler. The double-variables have to be sent / received via TCP. For this purpose they shall be put into / assembled from I/O-buffers.
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 RepliesI 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)
Attempting to convert a possible null value into date/time field. Any easy way ?
[Code]...
I've come across an error I'm not quite sure how to get rid of, I've got a listview with listview items making up the grid, I've got values coming from a database populating the cells however if there are any null values(in this case, there's null values in the date) it crashes my program. I'm not quite sure of a way to allow the listview to have null values in it, I figured it would default allow it but that's not the case.[code]....
View 1 Replieswhat is the code for allowing null values to appear on the textbox
Dim i As Integer
dg1.DataSource = bs
i = dg1.CurrentRow.Index
Patient_Profile.Txtpatient_id.Text = dg1.Item(0, i).Value
I have a databound DataGridView and use a button to control updates.
The problem is that if a db Column does not allow a null value an error is thrown ("Column <ID> does not allow null values") and then the datagridview automatically removes the row. This error is raised as soon as the user leaves the cell and before the update command is issued.
I doing a project for my office. In that I am showing the values and strings from a particular table based on the date range and vendor selection. It is working fine with the date range. Except within the date range if the particular reader has no data it throws an error message like dbnull string.
[Code]...
I have an SQL query that gets a max value so that I can decide the next value to use in an ID field. The code works fine when there's a matching result, but if the query returns Null, it throws a Specified Cast is Invalid error.This is the code I'm using:
LastID = DirectCast(SQLQuery.ExecuteScalar(), Integer)
What would be the proper way to check for a null value?
I suspect this is going to be one of those cases where within 2 minutes of posting myquestion, I finally hit upon the right combination of terms in Google to find what I'm looking for...
I'm trying to import my xls files to sql server, but i saw some values become null even though data in excel values are exist.
below is my connection string :
Code:
Dim cnstr As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=" & txtfName.Text & ";" & _
"Extended Properties =""Excel 8.0;HDR=YES;IMEX=1"""[code].....
This error occurs while i'm importing the alphanumeric values into text, but previous values are numeric (but string datatyped).