I'm trying to add a service company from a vb form to an SQL table. It works as long as I enter something in every field on the form. If not I get a syntax error so I thought I should check that the field values were not null
I've tried to add a sub to check for blanks but it's not working
btw the table will allow nulls for all fields
Private Sub btnSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSubmit.Click
Try
I used to run into problems with this in VB6, too...
If Not ds_Students.Tables(0).Rows(0).Item("ClassDay2").IsNullOrEmpty Then txtClassDay2.Text = ds_Students.Tables(0).Rows(0).Item("ClassDay2") End If This produces "Public member 'IsNullOrEmpty' on type 'DBNull' not found."
And is there a different test for fields of different data types?
I have a database with a table that is a child to many other tables. I am using this child table as a datasource for a datagridview. I am using comboboxes to display specific fields in any parent tables, instead of the user seeing the foreign key. Everything is fine. However, I would like to filter the BindingSource based on text matches between any of the fields in the child table and the corresponding fields of the parent tables.
I have a database with lots of fields, some of which are still empty and are to be filled in at a later stage. Is there any way of writing an IF statement (or any other method) that will allow these empty records to be 'shown' in my textboxes in Visual Studio, without receiving the error:
Conversion from type 'DBNull' to type 'String' is not valid.
I am building a vb.net application for a client, and there is a problem. I am connecting to a mySQL server, and using the UPDATE command to update certain fields to the specified values, however, once I run this code, the fields on the mySQL server turn EMPTY. Here is my code :
Sub updateresidents() 'MAKES NO SENSE; UPDATES EMPTY FIELDS ON mySQL SIDE??!!!!!!!!!!!!!!!!!! Dim connection As MySqlConnection
How to tell the program that if the field is empty to skip it and go to the next step. I have tried IsEmpty (but it tells me the variable IsEmpty was not declared), I have tried to use different If statements but in most cases I get the message "Conversion from type 'DBNull' to type 'String' is not valid."
I tried using an integer variable and setting it to 'Test = CStr(dt.Rows(I)("socSecNumber")).Length'. It works for the first step (which makes sense b/c socSecNumber is never empty), but when I set the 2nd and 3rd ones (TestFName = CStr(dt.Rows(I)("firstName")).Length TestLName = CStr(dt.Rows(I)("lastName")).Length If TestFName > 0 And TestLName > 0 Then...)
Then I am back to getting the message 'Conversion from type 'DBNull' to type 'String' is not valid'. I do not know anything about recordset and when I did try to use it it displayed the message something like 'get and set are no longer allowed'.
The entire function is below: Private Sub BtnCreateLetter_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCreateLetter.Click Dim SSN As String = TxtBxSSN.Text Dim dt As New DataTable() [Code] .....
Is it possible to include something in the SELECT from table? Such as: "SELECT * FROM" & Students & "WHERE" * NOT DBNull or I do not know if it is possible to use variables in the SELECT from table code but if it is I thought perhaps could make a variable named FieldContents and pass it to a function that would do something like: "SELECT * FROM" & Students & "WHERE" * FieldContents LIKE '[A-Z]'
I have example of Crystal Report document, in that document I have 3 fields from 2 tables (loaded from my database). What I'm trying to do is to access one of those fields (year field) programmaticly and pass only one value...let's say I only want to show year "2006." I've tried different things but nothing works 'til now.[code...]
with this, I can access to the field i want...but I don't know how to set or get any of his value...this code above only gets name of that field, I just put that for an example. I just want to do next: give user a chance to print different reports for different years, and I want to have some combobox menu.
why this code returns the property names as column headers and empty fields?
Dim table As New List(Of SalesPersonClass.SalesPersonClass) Dim i As Integer For i = 0 To salesPeople.GetUpperBound(0) table.Add(salesPeople(i)) Next dgSalesPeople.DataSource = table
I'm trying to use hyperlink fields in my gridview to pass certain values into another page using querystrings. On the next page I've put 'labels' that should be populated with data from the gridview, however nothing happens. This is my gridview code:
in my form, I want to display a 200x200 table each field containing a 16x16 image. There should be no space between fields, and the fields need to be selectable... how to create such table.
i 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"))
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
I have been using the code below to edit SQL database fields from the data stored in a dataset. Problem is I have to repeat this long code for each database field to be edited....I find this very tiring...IS THERE A SHORTER WAY OF EDITING SQL Database FIELDS. (Am using VS 2005 and SQL Server 2005
'3. Create an Update command Dim strUpdateAccounts As String = "UPDATE Accounts SET Description = @Description" 'create a SqlCommand object and assign it to the UpdateCommand property
Assume my form has four text boxes and it's bond with a Dataset, therefore The user can 1-4 fields. Typically I write one update statement that take four input parameters. Therefore I update the updated fields as well as non updated field. To do this in the proper way, how many update statements I have to write? Or How do I do this update properly? I use SQL server 2K5
I will post a sequence of examples and thought about sql injection, I wish the expert will correct any small mistake in what I will say so I can know exactly the possible danger.
The required is to create a function in vb.net that accept 2 parameter (table_name, fields_list) and return the result in datatable
Now, I am aware of that table_name and fields_list cannot be passed as parameter to the command object using .AddParameter
here is a couple of thoughts, what I would like to know is
1- which function is exposed to sql injection
2- Which function is more safe
Public Class Form14 Dim conn as New SqlClient.SqlConnection(connection_string) Private Sub Button1_Click( ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim r = (From p In db.Product _ Where p.Product_ID = ProductID _ Select p)[code].....
My problem is eventhought the request return an empty table (I tried with a count too) it consider the table as not empty and execute the code inside the "if"...
i have 10 of empty row which doesnt not have any data, this is happen because i click to many insert button insert data. Please show me the coding should i use to delete my empty row. For you info i have table name is Bundle and 2 column which is name and type .
connection.ConnectionString = " Data Source=Danawa;Initial Catalog=Store;Integrated Security=True" Try connection.Open()
Using myConnection As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & databasePath & ";User Id=admin;Password=;")
[Code]......
This did not work but did when i just tried creating the table and not the fields.
Have anyone developed a textbox where it is possible to display 2 fields in the textbox. We want to be able to show ID + description in the same textbox. (When user enter the textbox description may go away and the user can enter an ID)
In my first attempt to create a Class that contains something useful (if you will), I am a little lost what a sound way to proceed is. I am trying to make a table that has fields and records. Perhaps imagine a tiny spreadsheet. So, I create my Class. Properties might include the number of columns, the column titles, and the number of rows or records. I then think the thing to do is create a couple of structures to be used within the class. Thus far I have this:
Imports System.Console Public Class ConsoleTable Property NumberofCOlumns As Int32
[Code]....
Problems I am creating in my mind include:
1) In the Field Structure, could I make the FieldValue so that I can change the data type? Meaning sometimes I want an instance of a Field to hold a string,or an integer, or a decimal.
2) In the Record structure, for any given instance of one I don't know the number of fields it will hold until I create the new instance. I tried Public RecordFields(FieldCount) As Field in the Structure, but that's not allowed. I then used Public RecordFields() As Field, and then in my code used the ReDim method. Is there a better way?
3) With the Table Class, same problem. The number of records within any instance of the class needs to be dynamic.
What i'm trying to do here is login using a table and fields with username and password and also usertype in it. If the user is an Admin then it displays the the command button cmdAdmin and if not admin it disables it. This is the code that i currently have at the moment Hope someone can help me out and also i want to get rid of the username and password that's currently in it and use database instead.?
