I'm building a custom calendar control that queries our database to display corporate events. Here is the situation, there is an EndDate value stored and on the dev system one of the events have a NULL value. No big deal since it's only a test system, but might as well check before trying to use it anyway on the safe side. I figured the following code would work:
While dr.Read() corporateTable.Rows.Add(New Object() { _ Convert.ToDateTime(dr("EventBeginDate")) _
[code]....
The thing that really gets me is, at one point I had this:
Thinking that it should work because it should only evaluate the dr() if it's not NULL. However, it kept erroring out at the end because the value was in fact NULL.Why is it that even though I'm checking if it's NULL before using the value, it errors out at the part that doesn't get called unless it's not NULL? Does it have to do with the fact that I'm using the IIF() and it's evaluating the whole statement? Or, using the dr(), it evaluates at runtime?
I have a DataSet that contains 1 DataTable, and the DataTable contains only 1 row of data. I want to loop through all columns in that row and say:
Column name = column value
so for example if the column name is FAVORITE_FOOD and the value is pizza, I should display FAVORITE_FOOD = pizza I can get the column name from column.ColumnName and the value from Rows(0).Item(0), but for the life of me I can't put it all together in a simple loop.
i just want to ask how can i trap the deletion message appears whenever i delete one item in may data entry? im using vb2008 and sql as my database.i know the code in access. does anyone know its counterpart in vb2008? here's the code in Access 2003acDataErrContinue
This is incredibly urgent, I need to present this application in 3 and a half hours.My application checks against a data source to see if a value exists in the database and changes values depending on whether or not the value in question was found.The problem is that I've run the sql query with the value in question in SSMS and no rows were returned, and yet, my DataReader says it has rows.[code]val will only be returned True if the NumberToCheck (in this example 3235553469) exists in the database.Having copied the value of NumberToCheck into SSMS and testing the query there, I can verify that the query does work as expected.No, I can't populate a DataSet because of the volume of information in the table (+/- 9.5m rows). Even with the 'WHERE' filter, the query is too heavy on resources and eventually ends in an OutOfMemory Exception which is why I went with a DataReader.
I am running queries using sqlcommand and am trying to get the results from sqldatareader into a dataset table. It works fine when loading the datareader data as a row into the dataset table and writes it to a crystal report.I would like to have depending on the query results have the data in the appropriate columns and it only happens if the results are from all fields.
Dim CommandObj2 As New SqlCommand(sql, cnn) sqldr = CommandObj2.ExecuteReader() While sqldr.Read() Dim dataRow As DataRow = ds.Tables("NTable").NewRow()
[code]....
MsgBox(ds.NTable.Rows.Count, MsgBoxStyle.OkOnly, "Records Count")My dataset and table have the same name, NTable. Question again is how to populate the dataset columns accordingly.
I am having problem with datagridview. Actually I have created datagridview control used to display the data using sqldatareader. My problem is that How can I fill the data in textbox control when user selects the row in datagridview using coding. For e.g. my form is having a) Datagridview and displaying values of columns: Name, Address, City, State etc and textboxes: txt1, txt2, txt3, txt4. Now if the user selects any row from datagridview the selected value of Name is filled with txt1, address is with txt2, city with txt3, state with txt4. I am directly dealing with database with using DataAdapter.
I'm stuck on a problem that I haven't been able solve. I'm making a visual basic program that communicates with an SQL-database. The problem emerged when I tried to retrieve data from the database with the help of SqlDataReader and save data from every row to a list (Customer) with the help of Add-method. It turned out that eventually the list had correct number of objects, but the information was the very same in each object of the list.
I have a DataGridView that I'd like to load with data that I'm retrieving from a SQLDataReader running in a background worker as the data comes in (it's a query that takes a long time). My goal is for the user experience to be similar to searching for a file in Windows where the results appear in the list as they come in and you can still interact with the window.
I have it working with a background worker and data reader and I'm trying to add the row from the SQLDataReader.Read through using the BackgroundWorker.ReportProgress method. Everything technically works but the flicker is crazy and the form is unusable (probably not because the GUI thread is blocked but just because there's so much going on...) How do I make loading the datagridview "smooth"?
So here is the deal. I am making my own program for fun, and I have this road block. Basically I have a 'Parent Form' which we'll call 'frmMain' and I also have another form which we'll call 'frmSchedule' (work with me here)
I'm using an Entity Framework context, and sometimes would like to create a transaction so that the client can do multiple changes and then commit/rollback them all together.However, if many changes were made, and SaveChanges() was called multiple times, after which a rollback is called, entities that were commited already, will remain the way they were commited, and would not roll back.Here's how my transaction-relative functions look like:
Public Sub BeginTransaction() Dim context = HttpContext.Current.GetObjectContext() If Not context.Connection.State = ConnectionState.Open Then context.Connection.Open() End If
[Code]...
Not only does the test fail, but it also leave the ObjectContext in an unstable mode, because it still has invalid changes in it.
I have a list of items in a ListView and at the top of the list there is an item that is supposed to select all the items in the ListView. I can get it to select all of the items when it's checked but then I can't deselect any other items. I need the to know which item was checked, when putting the sender into a message box I get "System.Windows.Forms.ListView, Items.Count: 1, Items[0]: ListViewItem: {All}". How do I get the sender's item?
I have a form like that: What I need to do is when the user selects item1 from combobox a message will be displayed in listbox. My combobox has 11 items so I must have 11 appropiate messages to be stored automatically in listbox . (The message is appropriate of what item is selected from the combobox)
Here is the full code implemented : Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged Dim msg1, msg2, msg3, msg4, msg5, msg6, msg7, msg8, msg9, msg10, msg11 As String If ComboBox1.SelectedValue = "Item1" Then msg1 = "Ati ales item1 din combobox" [Code] .....
I have two issues I am trying to correct...First am trying to get my listbox1 to be the selected Comport used to do the send data and get data back.
My second issue is its requiring me to send two times to get my read data back as complete data and has odd shapes with the data I get back in front of and after the regular txt.
Beware, I am very new at this so please take it easy on me... Most help I did find was for older versions I only have the 2010 Visual studio Professional...
A function of my app is to encrypt a file with TripleDES. The problem is that when the app reads the data, encrypts it, and writes it back, the new data is appended. I need it to overwrite the original contents.Here is the code:
Dim DES As New System.Security.Cryptography.TripleDESCryptoServiceProvider[code]............
I have a situation where I serialized data from a dataset to an xml file as a method of backup.I am trying to get the data deserialized back to the dataset.But for some reason, I cannot get the data to persist back to the DB.I don't receive any error messages either.The first chunk of code is the serialization code and the second chunk is the deserialization code.I can show that the deserialization back to the dataset is complete because this code in the 2nd block DataGridView2.DataSource = Movie_dbDataSet.movie_tb - displays the data in correct form all it is all there in the datagridview2.I call the update method but it does not get persisted back to the db.[code]
Regarding my college project. i'm working on a sales system . i have a form which consist of all the following information( item code , item name , item price , quantity of item ) which is display using a data grid . data input by user using text box and all this information will be stored in a database(sales database) i'm using ms access 2007. the grand total will be displayed in a text box . and amount paid will be input in a text box too , my major problem now is how to i create a reciept that will have all this information of the purcase. i have a reciept button . what the next step ? i dont have any idea how to get the reciept done.
I am using VB.net 2003. I am working on a stand alone windows program that stores data in an Access database via ADO.net via MS jet 4.0 OLEDb. I have progress to the point that I would like to provide the end user the oportunity to back-up the data they have stored and re-install if they choose. I am envisioning a menu item for "maintenance" with sub-items for "back-up" and "restore". I can create the menu items, but I can not find any information on how the back-up should be done.
I am writing an automation program for an associated research HYPOT tester and one of my current problems is trying to split the data i recieve back from the box.Currently i have two commands i use TD? and SALL? both do the same thing but return different data. TD? when sent to the box will return the test results and of course there is no auto return when test is complete so i have to either set some kinda of timer to get the data after the test is complete or just keep pinging the box tell the test returns with either a pass or fail.my problem is when i ping the box with TD? it returns
"M11,ACW,test results{pass|fail},1.50,10.00,10ms"
What I am trying to do is use a split command to split that line into strings based off "," as my dilimeter. Currently i am useing this set up
dim resultstring as string = main.serialport1.readexisting dimresultarray as string = split(resultstring, ",",6) txtTestResult.Text = resultarray(2)
for the most part is does return the test results but other times it will either error out saying that resultarray(2) is out side the index or it will display one of the other strings (acw or 1.50).Is there a more accurate way to do this.I am also printing the full string pulled from the buffer into a text doc as a data log.
I have an xbap application that connects to a webservice to run different stored procedure. The webmethod loads the data into a data table and returns it to my xbap application. My program gives the user the option to manipulate the data. What is the best option for saving the data back to the database?
I am having a problem with an application that displays data in datagridview depending on a selection from a combo box.The problem occurs when I want to write the data back to the database.
I get the following error:"Update unable to find TableMapping['Product'] or DataTable 'Product'."
Is this because the table in the dataset is filled in a private sub? If so how do I make it public?
This is something that has been bugging me for a while as it is easily fixed but not desirable.I have a DataGridView that has 5 columns. The first is called ID.In vb.net the following line gives an error "Object reference not set to an instance of an object": dgvJobs.Columns("ID").Visible = False ' ERROR dgvJobs.Columns(0).Visible = False ' OK
Obviously using the name is much better than a hard coded value to reference the column but wondering if there is anything i can do to get this to work correctly?The datagridview datasource is BindingSource control with the datasource being a dataset.
I'm currently working on a program that would take the binary data from my access database and convert it back into jpeg format so I can store the images in a folder. I'm really new to VB so right now I'm pretty much stumped.
Code: Option Explicit On Public Class Form1 Private cn As ADODB.Connection
I have an existing WSDL which returns information to remote devices using SOAP. However, I'm writing a new app with Android which doesn't support SOAP so I can't use the existing WSDL and have had to code a new app which looks for a querystring from the Android app and returns the data in a JSON packet. I've coded the module which receives the data okay but I'm unsure how to send the data back in JSON forma
