VS 2010 Checking For Empty Field
Sep 1, 2011I have a field that I want to check to see if it has a value or not. But my code is not working. I am using:[code]
View 9 RepliesI have a field that I want to check to see if it has a value or not. But my code is not working. I am using:[code]
View 9 RepliesI'm writing a program for my class, which pretty much is an energy cost calculator. It takes 4 inputs from 4 text boxes and multiplies them, and the result is the cost. Well, now I have to come up with a way to check for empty text boxes and display a prompt to enter a number. I've tried inserting multiple codes to display a prompt and to no avail nothing has worked, I also receive the error "when casting from a number, the value must be a number less than infinity" error.
View 3 RepliesHow do i check if the dataset is empty? I wrote the following code:
[Code]...
In my application I load a CheckedListBox from text file apart from looking at the form, how can I trap the error of not completing the action?
View 1 RepliesHow will I check that the dynamic textboxes is empty;
Here's the code:
Imports System.Data
Imports System.Data.SqlClient
Public Class FunctionProcessor
Dim objcmd As New SqlCommand
[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 RepliesFor example, I clicked the Add Text box button, so it added 3 text boxes in the form (I used Dynamic text box so it can add multiple text box). When I input data to one of those 3 text boxes and then Save button has been clicked. It should checked whether the dynamic text boxes are empty or not. If there are empty text boxes, then saving data to db should not be continued and display a message telling the user that empty field(s) are invalid.
In the code below, it saves the data even if there are empty text boxes and I think because it is in the for loop, it checks the text boxes one by one and repeatedly displays the message box that I coded.
Here's the complete code:
Imports System.Data
Imports System.Data.SqlClient
Public Class Form3
[Code]....
What is the method call for checking to see if data was entered into a field? I am wanting a site to display an error message if no data was entered.
View 2 RepliesI 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'm a little confused about checking values in a database. What I want to do is see if a tuple such as the following exists:
[Code]...
The invoice_num is not null, it's blank: " ". What I want is to find if such an entry exists, where the invoice_num is " " and update it with a number entered into a textbox. I'm a little confused about if statements and cases in SQL, so if someone could point me in the right direction, that would be great!
At run time my application gives an error of "Conversion from type "DBNull" to type "String" is not valid. In my form only one field - Add_info is an optional field which might be filled or not by the user. Before, I had an error when an apostrophe was used so i updated the code as highlighted below. This in return removed the apostrophe error but generated an error whenever there is an empty additional field.
For irow = 0 To QryColSentDataGridView.Rows.Count - 1
If QryColSentDataGridView.Rows(irow).Cells(3).Value = True Then
Try
query = "UPDATE gprdsql.TblCollections SET system_time = '" & _
Labeldate.Text & "' where prac_no ='" & _
[Code] .....
I key-in data from textbox to datagridvie..........the date data the format datatable is:
[Code]...
We are bysy with making a crystal report in vs2005 / 2008
We want to print the address of a bussiness, see picture-1.jpg
If field-2 of the second record isnt filled in we get the the result see picture-2.jpg
In the crystal report we don't want to show the empty information of field-2, see picture-3.jpg Is it possible to create this in a crystal report?
I need to check if a Commodity entered into (TextBox1.Text) already exists on my table before i insert it. I'm having issues checking if the number of rows returned from my Select is equal 0? Also i'm wondering should i be checking for an exception and open/closing my connections each time i make a call to my DB or is the way i have it coded below OK?
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Try
myConnection = New SqlConnection("server=localSQLEXPRESS;uid=sa;password=12345;database=My DB")
myConnection.Open()
[code]....
I have a textbox that acts as a password field. It is supposed to contain a value at least 8 characters long and not greater than 12 characters in length. I need to construct an if statement that checks to see if there is at least 1 numeric character in the string and at least one letter in the string.
View 4 RepliesI have an array set up to receive the names of forms when they open. The form name is sent as a Form not a String therefore when I run my code I cannot check for whether the field is empty in the normal way (ie. array(1) = "") as the "" are only usable with strings!
Dim Forms(24) As Form
Dim i As Integer
Dim Free As Integer = -1
[CODE]...
I only need a solution to do the same as array(1)="" but for windows forms.
I'm using visual basic to code a program to help with weights and center of balance on aircrafts, as I'm my unit's new air load planner. The math isn't hard to do, it's just that much of it is trial and error, and redoing all the arithmetic over and over again until the aircraft's C/B is in acceptable limits can eat some time up. So, since i'm trying to learn programming I thought this might be a good way to use it for a real-world scenario.
[Code]...
I have a form and stored procedure that inserts the data from the form. It works fine except that if a field isn't filled in it doesn't insert a NULL into SQL it inserts "".
I've tried a few different ways but none seem to insert NULL, the one below still inserts "", can anyone point me in the right direction?
Here is the required part of the code, if you require more just let me know.
Dim rdr As SqlDataReader
Dim cmdInsert As SqlCommand = New SqlCommand()
cmdInsert.CommandText = "spPersonalDetailsInsert"
[Code].....
So if I enter nothing into address1 field it should write NULL to screen but it always writes NOT NULL. What does an empty form field equal? in classic ASP it was always "".
I have a couple of textfields in a Windows form. One of these textfields is allowed to be NULL. When I enter a value for every field, it is all inserted, no problem. When I leave the field (txtGewicht) blank, I can't seem to be able to insert NULL in Access Database.
If Double.TryParse(txtGewicht.Text, 0) Then
klant.Gewicht = Double.Parse(txtGewicht.Text)
Else
[Code]....
This is what I get:
"Cannot set column 'Gewicht' to NULL, please use DBNull instead"
So I changed 'Nothing' to DBNull.value, but it then tells me that System.DBNull cannot be converted to type Double.
Here's a sub routine that fills a data set with a table which I queried using an Inner Join statement. This output table, has all the required fields and the query works fine. However I want it like so:
If a student doesn't have a StudentPrediction.PredictedGrade Field to JOIN and it IS Empty.. Then I still would like it to display the students information just leaving the StudentPrediction.Predicted field empty.
You see I am using a ListView to display the data from when I fill the ListView, but it will only display for people who have a Predicted Grade naturally. So what steps would I need to take to ensure it displays all the information in the Student's table AND for the students who do have predictions that would also be displayed. If the student has no data on PredictedGrades then that column would be blank but the rest of the information still displayed.
Private Sub FillDataset()
Dim ConString As String = ("Data Source=USERSQLEXPRESS;Initial Catalog=StudentTeacherDB;Integrated Security=True")
Dim QueryString As String = "SELECT Student.FirstName, Student.Surname, Student.Email,
[Code] .....
I'm using the following to populate a listbox from a sql server:[code]Is Available returns true (It's a bit in sql) or false - Is it possible to replace this with something shorter, say a checkbox or tick image?Also, is it possible to only display actual data rather than the whole field including empty characters? I have a few nchar(30) fields, the above seems to include all 30 character spaces.
View 4 RepliesThis is my database: Here is my
[Code]...
I'm fairly new to ASP.NET & VB.I've been asked to take an existing textbox that is automatically filled with the current date and allow the user to either add a "+" or "-" and a number or a spcific number and convert that into a date.I underdstand the basic concept on how to do this, but I'm running into some problems using the proper commands in order for this to work.The Textbox is called txtDate.What I've tried to do is this:
If txtDate = '+' Or '-' Then
DateAdd("d", txtDate, today)
End If
Here is what the whole thing looks like:
Protected
Sub
DateEnter_Click(ByVal
sender As[code].....
datetime1 and datetime2now two fields are have data ( date )in table recordi want to update only datetime2 is an emptyi am using visual basic 2010 ( visual studio 2010
View 1 Repliesim trying to empty a datarepeater control because when the user selects the button twice it throws an error about double binding to the same control.i tried setting the datasouce to nothing and stating databindings.clear() but still didnt work?
View 1 RepliesThe data source is an Access 2003 table. I create the table in code and then populate it with 70 rows (each one empty apart from a date field). This unfortunately adds a 71st row (the placeholder for a new table row). Is there a way to stop this row appearing (I don't allow users to add rows anyway, only to edit existing ones, so this final empty row is just untidy and always empty).
Here is the code I use to create the 70 rows:
Conn.Open()
da.Fill(ds)
dsNewRow = ds.Tables(0).NewRow()
[code]....
I'm working on an automated program, and it needs to check the latest email on a certain account (which will be passed to it) every 15 seconds or so. Setting up the timer and the passing to the timer the username and password is easy, but it's the reading the email that I'm having trouble with. How exactly can I read the first few emails from my inbox and put them in an array? And after that, how can I access the body and subject, for example email.body and email.subject?
View 3 RepliesI�ve written an app that downloads from the internet with my.computer.network.downloadfile mehtod. The problem is it�s supposed to try a numder of urls and if there�s data, it downloads, otherwize the url is wrong. The utl adress is a combination of date and a letter, which the program gets from a database. So for every date, it checks all the letters as suffixes until it finds the right one. However the wrong ones tend to time out or something, which takes forever and also causes some errors. Is there a way to check if a url is valid at all, instead of actually trying a download?
View 1 RepliesMy DateTimePickers are retaining their values from one added record to the next. How do I empty their Value contents after each record is saved?
View 5 RepliesI do not know why this does not work. Obviously, I made a mistake somewhere.
[Code]....