I get a 'Conversion from type DBNull to String is not valid' error when I proceed to insert the row with a null cell value from my program to MS Sql Server even if the column is already set to accept null values in the database. How do I solve this? FYI I'm using an unbound datagrid, and I get all the screen values during runtime.
Property SerialNo()
Get
Return strSerialNo [code]...
If a column contains null dbnull value in sql server database then how can i replace it with "N/A" string when i view the database table in datagridview
View 2 RepliesThe problem is that if you never enter anything into a cell for a new row then that cell is never validated. This is a problem because I have columns that should not be null. I am doing the check in the row level validation and storing the information about which cells are empty that should not be empty. The row level validation works fine and the row level validation error indicator goes on,(red exclamation mark at the beginning of the row) but I also need a visual indicator on the individual cells that are in error.
I am thinking that setting the HasError property for the cells that are in error should cause them to display n error style (the default red border). Is there a way to this this either from XAML (perferably) or from code?Alternatively I could cause those cells to re-validate when the row editing is finished. Does anyone know how to do this?
I have the following query that I use to create a new record in a database. If I leave any field on the form blank, for example, it throws the error "Memo.Lastname" cannot be a zero length string. Other than that the query executes appropriately.
Private Sub cmdSaveMemo_Click(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles cmdSaveMemo.Click
If Len(Me.txtMemoID.Text) <> 0 Then
Memo.SaveMemo
[Code] .....
I want to add a new rows when cell leave event occurs.It shows error like Operation can not be performed in this event handler...
here is my code,
If PatientDataGridView.CurrentCell.ColumnIndex = 2 Then
PatientDataGridView.Rows.Add()
End If
I have a project due tonight and suddenly 2 of my datagridviews are acting funky while the others are fine.
I have 2 tables in an sqlce db. the first is books(id, title, copyright) and the next is publisher(id, name, bookid). I'm writing a vb.net frontend to access the data.
I have data bound datagridviews for both tables. Both have their respective ID columns hidden. The publisher dgv uses a combobox cell style to display the book title in the bookid column. So far so good.
I have suddenly run into a problem where if I have clicked in a cell on the books dgv and then click a cell on another row, the title changes to the id value. The publisher dgv also updates to show the id instead of the title.
It sounds to me like there may be a problem with the booktableadapter or bookbindingsource, but I don't know where to start looking for it. I have a 3rd dgv referencing an unrelated table, and it has no problems. The code for both the working and problematic dgvs are the same (only the control names are different).
I want to send the data that i just entered into a cell to an If-statemens to perform certain functions.I an using the following code just for testing purposes:
1
Private Sub DGVReceipt_CellLeave(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DGVReceipt.CellLeave
[code].....
I have set the datagridview.cellvalidating events. I want the user inputing in the cell and when error, the cursor cannot leave the cell when user key "TAB" or click in other where in the first time.But I find that it does not work in the first time. Until when I click the same cell in the second time, it trigger the action preventing user from leaving the cell and show the error message.
View 4 RepliesI'm using VS2010, vb.net, .net framework 4.0, and SQL Server 2008 Express on Windows 7 Pro with all updates installed. I have developed a website that uses memberships, profiles, and roles. I allowed the built in providers to create the aspnetdb.mdf file for me in the App_Data folder. I added a number of my own tables to aspnetdb.mdf so I would have a single database for all my site's data.
I am hosting the site on my own server. It uses Windows 2003 Server, IIS 6, SQL 2008 Express, and all of my software including the OS is up to date with the the latest servicepacks, updates, and all of the .net framework updates including 4.0. There are no updates left to install and I'm sure that my issue isn't due to a missing update or framework version.
I copied the aspnetdb.mdf and .ldf files from my app_code folder to the sql server express folder on my server and attached the database. I do this because I don't want the file to autoattach, because I will likely use a commercial hosting service in the future. I added a sql server user with ownership rights to the DB. strong text
I then modified my connection string in web.config to point to the UNC of my SQL Instance on my server and to authenticate with the sql server username and password that I set up with ownership rights to that database. I updated my membership, role, and profile providers in my web.config file to use the new sql connectionstring and I was sure to include the application="/" setting and to use before each provider.
I can run the site just fine from my development machine. I can log on to it and use all of its features. However, when I publish the site to my server I can access the site, both locally over my intranet and over the internet. I can navigate around on it and it retrieves all of the data from the tables that I added to the database myself, but when I try to log on to it or to create a new account (basically anything that uses memberships, roles, or profiles) the site crashes with the error and all of the data below.
I've checked to verify that the application name in my aspnetdb database is in fact simply "/". I've ensured that I'm running from an application pool that is using the 4.0 framework. Much of the googling and reading that I've done seems to indicate a problem with my providers, but I can't understand why it works perfectly on Casini (or whatever the development server is called) on my local machine but crashes on my web server. In both cases they are connecting to the same database.
I would be so grateful if anyone could tell me what I'm doing wrong here. Following are the full error displayed by my server when the site crashes and also what I feel are the relevant sections of my web.config file.Full content of error message and relevant sections of web.config are below:
Server Error in '/' Application.
Value cannot be null.
Parameter name: type
[code]....
i have a datagridview with records, when i select a row in datagrid i need to display the values in a textbox. please help me with sample code
View 3 RepliesI have a datagrid that will be accepting data from an external measuring device via the serial port. The grid is also open to editing records as well. Part of the process of making this grid user friendly is to intercept the "enter" key and move to the next cell until there is a value in the cell. This is only for some cells, other cells can be blank. I have worked out how to intercept the "enter" key from another post on this forum. Here is the code:
[Code]...
I have searched alot but can only find info on moving entire rows bound between 2 datagrids, but noting on moving single cells. I have some code below that works ok from DGV to textboxes but not from DGV1 to DGV2.
Dim i As Integer
i = DataGridView1.CurrentRow.Index
Form3.DataGridView1.Item(1, i).Value = DataGridView1.Item(0, i).Value
[code].....
This is my database: Here is my
[Code]...
when i leave the tab and move to another tab and return to last tab
this message show to me
http:[url].....
I have two comboxes inside a panel and have the following code which generates an error "Object reference not set to an instance of an object." on the line marked with *****
Private Sub cboJob_MouseHover(ByVal sender As System.Object, ByVal e As System.EventArgs) _
Handles cboJob1.MouseHover, cboJob2.MouseLeave
[Code].....
I have several date fields in a datagridview, in sql these are saved as navchar fields. If the user needs to clear the date they can do so by highlighting the field and pressing the delete key. This clears the date no problem, unfortunately it sets the field to Nothing or "" (a blank). I need it to set it back to NULL for reporting purposes.
Here is the relevant part of the code:
Private Sub dgvWeldingLog_CellEndEdit(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles dgvWeldingLog.CellEndEdit
Try
If dgvWeldingLog.Columns(e.ColumnIndex).Name = "dgvtxtDateWelded" Or _
dgvWeldingLog.Columns(e.ColumnIndex).Name = "dgvtxtFitCheck" Or _
[Code] .....
If there is an error in the data entry then the form cannot be saved. When I trap DBNull.Value is says it is equals to "Nothing" and not "NULL".
I want to display a message if the value of cell of my datagridview is Null.
View 1 RepliesWhat im trying to do is check a row for null values in my datagridview before saving the data back to my access database, in particular the first columns cell of the new row being added. This is the code I have so far'
Private Sub LatheprogramsBindingNavigatorSaveItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LatheprogramsBindingNavigatorSaveItem.Click
Dim test As String = Me.LatheprogramsDataGridView.Columns(1).ToString()
[code]....
I'm having this exception while trying to get the value of a cell from a table.[code]...
View 2 RepliesI have a program in which I am doing a sql select on two tables with an outer join. In one option of my search I need to show all items in both tables so some items in the row will come back with a null value. I am familiar with using the DefaultCellStyle.NullValue = which works great when replacing Null values with the same value.
I am in need of replacing the null value in column 0 with the value in column 10. I think I am close but have not had any luck researching this on my own. Here is what I have.
dgvInventory.Columns(0).DefaultCellStyle.NullValue = CStr(dgvInventory.Item(10, ???).Value) if I replace the ??? with any value I get that rows data but all null values become the same, what can I do to tell it to replace the current rows column 0 with the current rows column 10 if column 0 is null.
I have the following code that checks if the value in a cell contains a nummeric value.
Private Sub dgvOrderRegel_CellValidating(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles dgvOrderRegel.CellValidating
Select Case e.ColumnIndex
Case 4 'Aantal
If Not IsNumeric(e.FormattedValue) Then
[Code]...
I have one data grid which contains a column which contains long string values. When I edit it, the text box which appears is very small. I want to increase the length of text box.
View 2 Replieswhat is code i should use if i want to prevent user not to leave empty word in text box after user click save button. i am using visual studio 2005, database sql 2005.
View 2 RepliesUsing VB.Net, I am reading an Excel spreadsheet does anyone know what might cause a cell to be read as VBNull when it contains data?the cell clearly contains data. and what is extra weird is all the same cells in the rows before and after the bad one have the little green triangle in the upper left corner, indicating an error - but they all read fine the cell that reads as NULL is the cell in row 4 above
View 1 Repliesusing strongly-typed ms access 2007 database , vs 10 i have a problem with datagridview filter i have 4 columns and allowDBnull is true , null value is empty my problem is that i need to have 4 textbox to filter the columns so i used in the texchanged
Me.PartsBindingSource.Filter = "Convert(partsn, 'System.String') LIKE '%" & TextBox1.Text & "%'" & " and Convert(description, 'System.String') LIKE '%" & TextBox2.Text & "%'" & " and Convert(Position, 'System.String') LIKE '%" & TextBox2.Text & "%'" & " and Convert(model, 'System.String') LIKE '%" & TextBox4.Text & "%'"
which works just fine , except for the rows which contains any null value as those rows are hidden all the time once i change the text, even when i clear the textbox they keep hidden i can only see them once the form is loaded to cut it short, i need to make a filter to the datagridview , that filter should show the rows even if one of the cells is null?
I am trying to get the cell value from a particular cell in a DataGridView table but am having a little problem with the syntax.My research suggests that I need to use the command:
DataGridView.Rows.Item("Index of Row").Cells.Item("Name of Column").CellValue
but when I create the command:
x = DataGridView1.Rows.Item(0).Cells.Item("Dec").CellValue
[code].....
am converting a old vb.net program to WPF and am having trouble. I imported some data to a datatable and dumped that into a datagrid. I now need to go row by row and extract the cell values and use them to update the appropriate database record. This was working in my old program using:
For i = 0 To DataGridView1.Rows.Count - 1
cellvalue = Me.datagrid.Items(i).Cells(8).Value).ToString
(insert to database) etc
[code]......
I have this piece of
Private Sub FORNECEDORESBindingNavigatorSaveItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles FORNECEDORESBindingNavigatorSaveItem.Click[code]....
The idea is to detect if the cell of the first datagrid column is null and display the message. However, the code is not detecting the cell as null and the table adapter is throwing the OleDb exception.
Using VB.NET How to get Datagridview cell value.
I want to insert a Datagridcell value in the table, How to get datagridview cell value.
I am creating a POS system, but there are a couple of things that I cannot get my sales form to do. It contains a datagrid view of the table containing columns code, description, Qty, total. After the code has been entered, I want it to load the description automatically. After the Quantity has been entered, I want it to give the total amount for that Item + the total amount for this order.
[Code]...
