I am having a ton of trouble trying to check if a record exists. I continue to get a data mismatch on my command.ExecuteScalar().
Code:
Protected Sub btnRegister_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnRegister.Click
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I am trying to write(what I thought would be a simple piece of code. I was wrong.
What I am trying to do is to get an application to check if a file exists, However, I have it wrong as the file obviously does exists, but when I run the application it tells me it does not.
Imports System.IO
Public Class check
Dim checkfile As New FileInfo("C:\HelloWorld")
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I'm using then next method to check if a directory exists but it seems it doesn't work.
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im trying to make code to check if a file with the same name exists twice in the same dir one with .dds and one with .veh file extentions and if they do put in a listbox but if only one exists then it puts it in another listbox i have made code to filter .dds in to one listbox and .veh in another but i dont know how to make the "check" if they are both there
this is the code i have to split them at the mo
For Each files In dir
Dim path() As String = files.Split("\")
Dim chunk As Integer = path.Length
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but i wanted the Else for the .dds files that dont have the matching .veh file
I am trying to check whether username entered by user is already exist or not in database. But, I dont know how. The codes are below.
If TextBox3.Text = TextBox4.Text Then
Dim conn As New SqlConnection()
Dim cmd As New SqlCommand()
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I think this is a really simple question to answer but I can't find a better solution. Basically I am importing data from an external source and as I go through importing each for I am doing a for loop to see if the row already exists; this is taking a life time and I feel it is a very simple way of doing it. Is there a better way to see if a row already exists using specific columns and key indexes?
View 5 RepliesI'm using ADO.Net to work with an Excel Document. Essentially, I'm looking up values in a table called "source" and creating a new table called "result" which will be populated with the results of my query.
I have a couple of questions.A) How can I check if a table exists and create a new one if it doesn't? B) Is a table the same as a sheet in Excel?[URL]...
I haven't used System.IO before, and I'm a little stuck.I need to check if a file exists, for example C:Documents and SettingsverraineDesktopSURNAME Firstname v1.docx, if this file exists the filename has to become v2, and so on. Usually there will only be a v1, but in the case that a clients position changes we have to be able to save the new version without overwriting the old one.
How would I be able to do this efficiently? I'm uncertain to say the least. Because, if I manage to find out how to save the file as a different number, that's alright, but if that next number exists as well? I can only think of ways to do this that require a lot of code.
i have a checkbox on a form, which is of type boolean in the database .when the user check the checkbox, before the data enters the database, the program should check if there exists already a "1" on the database for this field.If so the user is not allowed to check the depot.
View 5 RepliesCompletely new to ASP.net
Page Language="vb"
Microsoft .NET Framework Version:2.0.50727.3603; ASP.NET Version:2.0.50727.3082
I want to check on the server for the existence of an image, then if it does exist, display the image wrapped in other code. E.g.
if "/images/name.jpg" exists then
<div><img src="/images/name.jpg"></div>
else
Do nothing.
Seems really simple to me but NOTHING I have tried has worked (compilation errors). I've tried examples using system.io, DIM stuff with 'FileInfo', Set fs. FileInfo examples produce 'not defined' errors, 'Set' says it's outdated and not used anymore and so on.
I want to check if an Outlook folder exists, if it doesn't then create it & if it does then carry on with other code. I can create the folder as a sub folder of the Inbox but once it is created I get an error because it is still looking to create when it's already created. I have tried to capture the error but still no joy.
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I've created the following function and thrown it inside of a timer:
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It works, but it keeps trying to open media player for each process it looks like. I need to continuously run the function so that Media Player opens when it's closed.how to make sure it opens only once when the process doesn't exist?
I'm checking is a file exists as follows.
If txtGradeObs.Text = "" Or Dir(txtGradeObs.Text) = "" Then
MsgBox("Specify the Grade job of Obstructions", vbExclamation, MsgBoxTitle)
Exit Sub
End If
I get an error if the drive does not exist - i.e. G: rather than C:. It used to work in VB6. How can I get it to work.
I'm trying to download files using the Net.WebClient call to DownloadFile
Using client As New Net.WebClient()
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Is there a polite way I can ask for the file instead of calling DownloadFile, and handling the exception ?
I am adding the text of a label into a datagridview. But before i do the insert, i want to check if the text does not already exist in the datagridview.
View 1 RepliesI have been on MSDN about this and searched but it's not quite telling me what I'm after. I've extracted a list of file names from an Excel spreadsheet and want to check whether they all exist in a directory which a user can select in a text box. It feels like I'm nearly there with it but currently my listbox is displaying everything, I want it to just show the files that are missing. I'm a beginner so I'm not exactly sure if I'm even telling it to compare the two things properly, I've tried a couple of ways of checking if a file exists but neither seem to work.[code]
View 1 RepliesI have a small database. 2 main tables called CaseDetails and Checks.Each record in CaseDetails can have 3 checks recorded against it in the Checks table. But can only have one check of each type (check types 1, 2, 3).I have 3 linkbuttons which will take the user to the input form for each 'check'. If a 'check' already exists i want to hide the linkbutton that takes the user to that 'check type' input form (the 3 input forms have different fields).So what i need to do, is connect to the SQL database and see if a record exists for each 'check type' and hide the linkbutton to prevent users from entering another record with the same 'check type'?I have tried reading the reults into an array and examining that array, but havent been able to do so.
View 5 RepliesI have a datagridview which is populated from a datatable. This works fine. But if i run it more then once i get a column name "example" already belongs to this datatable. Ive tried everything to clear all the columns of the datatable and the gridview but still the same
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I have a tenant details form that has a field called TenantID, I also have a Lease table that also has a TenantID field, what I want to do is click the lease button, check to see if the lease already exists, if it does open the lease form to that record. If not then open the lease form to a New record so the user can enter all the information for that lease.
I am trying to use the below code but am having a little trouble understanding how it all works. What needs to be declared, what doesnt
HTML
Private Sub btnLease_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLease.Click
Dim fm2 As New LeaseDetails
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Working on an VB/ASP website in Visual Studio 2008. Getting the error "You cannot add or change a record because a related record is required in table 'abc'
It is true that table xyz (the target of the INSERT) is in a parent-child relationship with table abc. The PK in abc is a column RequestID_lng. The FK column in xyz is also named RequestID_lng
This is the only relationship these 2 tables are in.
I am trying to add a row in xyz with a value of 45 in the FK. There is already, previous to this action, a row in table abc with a value of 45 in the PK. So the parent already exists for this child.
I have used the watch window to copy my SQL code for the INSERT query that is being executed. I pasted that code into a new query in the Access DB and executed it without problem - it actually added the row that .Net should have.[code]...
I am importing alot of data from a text file into an access database with the code below. (From a Comma delimited text file) The problem is that I do not want to import duplicate records. I have the "IDNr" column in my access database set to "not allow duplicates" and need my code to check if there is already a record in the database before trying to import the data. Otherwise it will just give me an error or not import the rest of the data. I could do to make sure that there are no duplicates for the IDNr column?
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I am using VS 2008 and MySQL. Which one of the following methods is efficient or a proper one to check if record exists or not before making an attempt to insert.
1. HasRows Property.
2. Select Where Exists
3. Select Count(*)
Or if there is any other appropriate method ( which i am not aware of ) available to do it in vb.net ?
At the moment when a user logs into my system it checks to see if a job exists, if so the records are put into a datagridview. However, if there are no jobs in the database I get an error.
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i can't find any wrong, if record exists then updated the record but only can insert the new record.
cannot updated the record.why?
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I have an default.aspx page that I'm trying to have redirect the user to a different page depending on whether or not their deviceId is stored in the SQL Server database. It should direct the user to the login.aspx if the record for the user is found or to the newdevice.aspx page if there was no record found. I want this to occur on Page_Load but have not been able to figure it out so far.
View 3 Repliesthe next code is working but when I try to insert an existing record, it gives me an error and I want to add a msgbox to let people now that the username is already taken.Only the username cannot repeat on the database because it's the primary key.. the rest of the table rows can repeat.
Dim cn As New OleDbConnection
cn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Fabio\Desktop\Telemoveis\Telemoveis\Db_Tel.accdb"
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I'm updating an app for children I wrote in VB6 to VB2010. It uses a rather extensive MSAccess Database. It works perfectly but I need to update it to utilize better speech technology. I have read a lot about SQL and can't find how it is useful for anything accept business applications that add, delete or update records as long as you hard code in a name. I don't use datagrids and I never display a table. how to do a few things, I can figure the rest out.
In VB6, I had:
Option Explicit
Public db As Database
Public rs As Recordset
Public Reader As Recordset
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If you have been reading my posts I'm trying to learn this ADO.net code. So I have been reading and coding and I have a Question. How to I know in .net, if the record exists to make the decision to Add New Row or UpdateRow? Here is the code from the web I have been working with to better understand this, I could use some help on the decision making code needed to Update or New row.
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My tables are PURCHASE and SALES...In PURCHASE table, fields are CODE(primary key), PRICE, DATE, TOTAL, QTY...when I'm entering datas in form and when i click submit, the datas stored... but when i enter same DATA(CODE), it is showing error...i don't want to show the DEFAULT ERROR message...so, i want to search whether the CODE is already in database or not...i.e When i click SUBMIT button, 1st it has to search whether the CODE is already PRESENT in table or not. if it is not there, DATAS have to be stored. otherwise, it has to DISPLAY MESSAGE BOX.
View 4 RepliesI have a bit of code that goes like this. [code] The problem is the MyInclusion = "Aspire Inclusions Pack" and the TblPackages. Rows(n). Item("fldPromotion1") also = "Aspire Inclusions Pack" BUT the CheckTrueOrFalse is FALSE. I need it to return a TRUE value for CheckTrueOrFalse.
View 1 Replies