Deleting A Database Row In A Dataview InvalidCastException
May 7, 2010
Visual Basic 2008 I'm trying to delete a row from an Access database in my DataGridView using a coded delete button. I have an input box asking for a row number to delete. It works fine except if I have anything but an interger, leave the input blank, or hit the cancel, I get :
I am using Visual Studio 2005, Version 2.0. Coding a windows application with VB.NET.I am trying to use a textbox (txtLogCall) to display matched results in a datagrid. I have added a bindingsource and have the dataset and tableadapter.
I have set the databinding tag of the datagrid to the field that I want to use as a parameter. The textbox is for an Caller's Name, so I have set the datagrid tag to 'EmergencyCallerIdentification' that is in the table.
If want to do a DataView.Find on a DataTable that is already 'ORDERED' by the Column I am seaching, so a DataView.SORT should not be necessary, but it throws an Exception if I don't give a .sort command before the .find command. Is there any way to avoid this apparant duplication ? and speed up the search time. Its a very large table - 1 million rows. I am using VB 2010
I got a problem with dataview that get data from datatabel (Col1 : ID,Col2: Time) and I'm sorting by Time in desc ... when the values for example {40.21,80.21,70.25,25.2} the dataview sorting them as I need but when one of values goes above 100 for example {40.21,80.21,100.25,25.2} the dataview always sort the highest number is the buttom, I don't know why ..
This is a sample code
Dim dt As New DataTable dt.Columns.Add("ID") dt.Columns.Add("Time") [CODE]...
I'm having problems with an Invalid Cast Exception when I try and read a PDF from a database as a BLOB. I am able to write the files into the database no problems at all,however, when I try to retrieve them I just get InvalidCastException.Here is the code I'm using:
Protected Sub btnPDF_Click(sender As Object, e As EventArgs) Handles btnPDF.Click ' Request.QueryString["docid"].ToString(); Dim docuid As String = "b39a443d-ccfd-47f4-b333-f12cd94683d6"
I create a DataView that load a table from database.
Dim da As OleDb.OleDbDataAdapter da = New OleDb.OleDbDataAdapter("select * from customers order by name", cnmain) ' I load complete table
[Code].....
�Thst's all I need? Because when I recover the first row of DataView filtered, it appears the first row initially loaded when I don't put filter.. �Do I need to refresh DataView to view te changes?
when i had 3 text box then i did the following code and it worked for me also:
Imports System.Data Imports System.Data.OleDb Public Class Form1 Dim con As OleDbConnection
[code]....
in the above code ,depending on the textbox3.text,i performed all the deletion,so it was easy now i have got a three of combo box and three text box....... i filled the combo box with the database entries.....now i want to perform deletion depending upon the selected items of any one of the three combo box........i cant get the logic of the where portion in the delete syntax.....
There's a combobox with questions and a listbox with questions of the chosen answer(s).I have already to add and show the questions, answers.Now I wan't to delete the answer(s) (in the listbox) of the chosen questions I have this already
con = New OleDbConnection(providerStr & dbLoc) con.Open() Dim command As New OleDb.OleDbCommand("DELETE FROM Answers WHERE questionId= " & 0 & " AND answer='" & lstAnswers.SelectedIndex.ToString & "')", con)
I can delete record but it only checks for the username.How bout for the password?Can I use
("delete from tblogin where username=('" & txtUsername.Text & "') AND password=('" & txtPassword.Text & "') ", sqlconn)
so that it can also validate the password?
Private Sub btnDeleteuser_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDeleteuser.Click sqlconn = New SqlConnection("server=CHERRIE-PC;Database=yss;integrated
I've been working on a little sidebar project for fun about a casino. It may have a couple of card games like, war and eventually 5 card draw. I haven't begun any card programming yet because I'm on a screen that shows players.
I have a form with a listbox bound to a tableadapter. Users can select from a combox, that has a list of users in it, then click "Add" to add it to the listbox and remove to remove it. This part works fine. The problem comes when updating the database:
ive added a datagrid view to my form and ive also linked it to a database which displays the details i need. but what if i want to delete any rows(records) from the datagrid or edit. i need it to also change in the database. whats the coding? ive tried n tried but cant seem to get the code. its vb.net 2005
what happens is i have a weekly salary table and once a week an administrator computes the salaries and it will be saved there, i want the delete code to delete the already saved record with the same Emp_ID as what i'm trying to save. my problem is i don't think the code i put deletes the record because it will still tell me that there is already an Emp_ID the same with what i'm trying to save..
so far this is my code..
Dim cnn As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source = C:UsersFlorieDocumentsVisual Studio 2008ProjectsPayroll SystemPayroll Systemobjx86DebugPayroll_MaryRoseAn.accdb") Dim cmd As New OleDbCommand
I have created a service that will update a table. <foxpro to mysql>Before the update it will delete all the data in a table<mysql> and then insert the record from the dataset<from foxpro> one by one.I have more than 5000 records and it is very time consuming, now I would like to ask for some idea if there is a way in vb.net to only insert the data that have been recently added to the table<in foxpro> to mysql table. Is it possible in vb.net to know what has been added in the table?
I have records in my datagridview (from database(ms sql server 2008 r2)). What i want to do is to insert the records selected by my datagridview checkboxcolumn and IF POSSIBLE automatically delete a record if the records to be inserted are equal to the records inside the database. (Hoping you got what I want to say.) For example. I have an A,B,C(child) that is under XXX(parent) in my database and I'll be inserting the A,B(child) again but it will be under YYY(parent). The old record in XXX will be deleted except C. I just want a possible DELETE STATEMENT These are what I've done so Far :
Insertion of record to database Try connectionString = "Data Source=***;" sql_connection = New SqlConnection(connectionString)
I have a form with textbox controls that are bound to the database. I have a bindingnavigator within the form, when i use the save & delete buttons on the bindingnavigator toolbar they seem to work but when i check my db nothing has changed. I have tried to work around this problem by updating the saveitem code using the code below.[code]
im having a problem on double execution, this is a part of audit trail on my system, the DELETE FUNCTION is working, but it aint updating, im getting an error - it says that "Syntax Error on update statement" on i tried to manually query it on my access and it is working, i bold the statements that affectes the UPDATE function
Dim burahin As String burahin = MsgBox("Are you sure you want to delete a customer from the database", vbOKCancel + vbQuestion, "Administrator") If burahin = vbOK Then
I start my project in vb.net backend is sql server i have completed my design now i start my coding but i am confused for connectivity code whether i used dataset or datable which is good? please give me best connection code for retriving,updating and deleting data from database..
I used the wizard to create a datagridview and then binded a grid to an access table.Data show up fine..But I can't dete records via the bindingnavigator.Hit the delete button then hit the save button ?Data does not get updated in the backend database.My properties are set to true for adding and deleting.
My project involves making a table database that displays student number, surname, first name, homeroom, and grade avg. Through SQL commands, there must be functions to add, update, delete, search by field, and save records to the database.I have already set the database up just fine and displayed it in a DataGridView. Through the DataGridView, I was able to go to the "Add Query" area, and I successfully made the queries necessary for searching by field. However, when I try to do anything other than a search using the query builder (ie start my SQL command with INSERT INTO or DELETE FROM), I ultimately get the message "Failed to get schema for this query"For example, this SQL code (to add an entry to the database) worked when I was in the Query Builder (and the entry that it made is still in the database), but when I finally tried to confirm it, I got the "Failed to get schema for this query" message.Being unable to add entries to the database this way, I tried to do it with textboxes on a form. Each textbox will have one of the fields, and at the click of a button, they would be put into the table. My code is below. I do not know what is wrong withit. When I run it, my fields do not appear on the DataGridView immediately, but I must run the program again to see it. The time after, the entry is gone. So I am not sure how exactly such entries are to be saved.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Try
I am trying to delete rows of an .sdf file using the Database Explorer utility of Visual Basic. When doing so, I get the following error message:No rows were deleted.
A problem occurred attempting to delete row 1.
Error Source: Microsoft.VisualStudio.DataTools. Error Message: The row value(s) updated or deleted either do not make the row unique or they alter multiple rows(48 rows). Correct the errors and attempt to delete the row again or press ESC to cancel the change(s). It is correct that the data in the rows are not unique (and not supposed to be; there is no "error" to correct), but why should this prevent deleting them?
I have an Access table in which I connect through ODBC commands. I want to delete the 50% of data rows from it. Can anyone knows a string to write for doing that? ALARMLOG is my table. In MS SQL I tryed succesfully the following command :
I have been trying my hand at this for some days now and just cant get anything to work. Below is the code im currently using to delete a row from a database table, the problem when trying to build the project line 5 is giving this error about the value con" Value of type String cannot be converted to 'System.Data.OleDb.OleDbConnection' "
Dim con As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & "Data Source=Customers.mdb" Dim cnn As New OleDb.OleDbConnection(con) cnn.Open()
[CODE]...
I have also tried using this code below, but to no success. Im basically just looking for something rock soild that i can use to accomplish this task. Been stuck on this for quite a while now.
I have spent several hours trying to delete a row and insert a row into an Access database using the OLEDBDataadapter and dataSets without any success. I don't get any errors it just doesn't update the datatable. Here is the last version of the code I have been trying to get to work. I have done a lot of searching and have
Data save Private Sub SaveNumDte(ByVal ltoNum As String, ByVal ltoDate As Date) Dim numTotal, x, MaxRows As Integer
Dim CustID As String = txtSrchCustID.Text Dim FirstName As String = txtNewCustFName.Text Dim SecondName As String = txtNewCustSName.Text If CustID And FirstName And SecondName = "" Then MsgBox("Please enter a term to search by") EndIf
This returns "Conversion from string "" to type 'Long' is not valid." I was wondering what the error is and how it's possible to fix it? The other questions that I've looked at were mostly to do with variables assigned incorrect types, but I think that isn't the issue. It occurs when all of the variables are empty.
OK, this is going better, now im stuck in the mud again, i am trying to get a form to print,this works now, however i would like to enable a few frames with text boxes for a few seconds to allow the printer to print the text in black instead of gray. he error i am getting is this, as the timer disables:" Unable to cast object of type System.Windows.Forms.Timer' to type 'System.Windows.Forms.ToolStripMenuItem'. "