I 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.
On a button click I need to test whether or not an array has been filled, if it has the user gets linked to a new form otherwise they receive a message box telling them to first assign values to the array.
I've tried 'If MyArray Is Nothing Then....' and 'If MyArray.Length < 1 Then...' but neither seemed to have worked.
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 "".
This is my problem.I have a field set up in MS Access to Boolean YES/NO, this field is populated when the user check a checkbox on a windows form. If the user check a checkbox, the value is written as checked in the data field (MS Access).The problem is when I search for the user information, I need the information from the Data base to populate(return) to the windows form. Example: If I enter a users phone number and the user data is present, the form gets populated with the information the user previously entered which was store in the database.Example: If the user selected checkbox1 and submits the form. When I search for the user info, the check box should check(populate) because the user had checked it on submit.Here is what I have done:
[code]...
I am getting the check value correctly in the database using a Boolean.Here is one of the errors I am getting. Unable to cast object of type
'System.Boolean' to type 'System.Windows.Forms.CheckBox.I am having trouble putting the codes in a code tag or block
How could you, update the fields on database if its data type is Y/N, and the method of updating is a checkbox??
View 1 RepliesLets say I have a form with several Textboxes that are all bound to "bindingsource1". I'd like to be able to check the field data type each textbox is bound to. Something like this,
Dim ctl As Control
For Each ctl In frm.Controls
If ctl.GetType.IsAssignableFrom(GetType(TextBox)) Then
[Code]....
I am building a data based application using VB 2008 an SQL Express. I need to create textboxes on my form using code, (With & End With) method. I need a simple code string that will allow the app to check if the field to wich the textbox wil be databound is Nul, If so the textbox will not be created.
View 8 RepliesWriting an asp.net mvc app and i have something like this...
Public Class AA
'... has some variables...
End Class
Public Class BB
[code]....
So, now in my program, i just want to copy object of type AA to an empty variable of type BB?it makes sense to do this, as i expect all the fields in AA type object to be copied to the newly created BB type object, and the ExtraVariable in the BB type object i would (will) just assign a value to it later (after the copy) on my own time!!I know copying BB type to AA type would not be appropriate as there would be lost data!But im trying to copy AA to BB, I've used both DirectCast and CType to do this, and i keep getting "unable to cast" error!
Note: I'm using vb.net (but can read c#, no problems)
I am trying to edit a dbf table. I would like to be able to rename field headings and change the field type, ie string or dbl, and the size of the field. is this possible to do with vb.net. I have connected to the dbf file but after that am lost on what to do.
View 3 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 RepliesAt 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 have a Boolean that writes to a data field. The data field(column) is set to YES/NO, if the user check a checkbox, the value is written as check in the data field.The problem is when I search for the user information, I need to get to form to the state it was in when the user submitted it.
Example: If the use select checkbox1 and submits the form. When I search the form, I need to make that particular check box check.
[Code]...
I am writing a scripting language which used .net for execution. Now I have written a function which accepts an object and return a set of numeric values. I wanted user to pass any numeric array (e.g. integer,single,double,long) and I could return values in that format. I mean user can retrieve value in any numeric array type rather than specifying an array type. E.g.
[Code]...
I am pulling data from a local MSSQL database using a stored procedure, then send the data to a web service. Every part of the component works well except for a pesky problem will a DBNull being returned from the DataRow field, when I know that the field is not null and has valid data. The database and associated INSERT statements that add to this field are designed to not allow NULL entries. When I debug break the program on or right before the line that throws the error I see that the field has valid data for the current row.If I add a null check to the code (as below) the operation continues as normal:
Dim dataResultsTable = Me.myViewTableAdapter.GetData(int)
For Each myDataRow In dataResultsTable.Rows
If worker.CancellationPending Then
[code]....
Why is the read operation returning DBNull instead of the data in the database?
EDIT: Just to be clear, the operation does return the proper data, but the data is not being saved into the variable.
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 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 RepliesA really boring question, sorry, but I really don't know that yet ;) I've tryed always string.empty, but with a decimal, there is an error.
View 3 Replies[code]... Check Datagrid Is Empty?
View 1 Repliesi have a dataset that takes results from a select to a sql database. the select returns rows and sometimes returns no rows. how can i check if the dataset has no rows from the select? [Code]
View 4 RepliesI need to check if a .txt file is empty, if it's not, the code will read the file and process the information.I know how to read .txt file. Is there a way to check if the .txt file is empty? not an empty line just completely empty?
View 3 RepliesI was wondering how to check if a list box is not empty I have inserted my code I want t check if there if text in the listbox and if there is no text do some thing. I have put the line of code i am having trouble with in red
result = MsgBox("Are you sure you wish to make the required number of lockers", MsgBoxStyle.YesNo, "Confirm Order")
If (result = MsgBoxResult.Yes) Then
CheckLevels()
If lstOrder.NoItems = True Then
[Code]...
I've done an internet search to determine if I can detail if a SQLDataAdapter is empty after running an SQLCommand? My research so far point I can't check if the SQL dataAdapter is empty until I bind it to a dataset/datatable. Ideally would not like to run another SQL command to do a row count to determine if query retruns rows or not. I'm populating a datagridview and would like to alert the user that there is no data to view. What's the most efficent way to check if an SQLDataAdapter is empty?
View 4 Repliesi want to insert the data into the table only if the table is empty, so for that i need to check the condition to check whether data already exists in the table, if present then i want to empty the table before inserting the the fresh value.
i know how to insert and delete the data only prob is to check the condition. so please can any help me out in this.
TO INSERT
Dim comUserSelect As OleDbCommand
myDateTime(i) = DateTime.Parse(arr_dateTime(i))
' Console.WriteLine(r("P1"))
[Code].....
In Visual Basic 2010 I have a PictureBox control which i need to check in code to see if it does not contain an image.
View 2 RepliesHow to test the stacks if it is already empty? I tried Stacks.IsEmpty but unfortunately I have an error says:
IsEmpty is not declared..
Is there any way to test if the stack is empty? When I'm typing (after dot) there is no IsEmpty properties of the stack.
Possible Duplicate: Checking for an SQL result in VB.NET
I have login form which is redirect user for their levels but before to that if there is no any user on the data table I would like to redirect to create admin form. I have all the forms but I didn't manage to redirect them because I don't know how to create statement.
Dim con As SqlCeConnection
Dim command As SqlCeCommand
con = New SqlCeConnection("Persist Security Info=False;Data Source=.database.sdf;Password=********;File Mode=shared read")
con.Open()
[Code] .....
I have this code is working. What to write for
Private Sub frmlogin_Load(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles MyBase.Load
End Sub