I am using VB.net within Visual Studio 2008. I currently have GridControl where one of the columns fetches a real number from the database. Whenever I try to remove the value I get a red 'X' saying that the input string is not the right format even though I know it can display null because the row underneath fetched a null value for that column.
View 1 RepliesI am using VB2008 on Win XP SP3 and an relatively new using this language. I would like orientation or advice on how to proceed given the following:I execute an SQL statement, such as select * from MyTable where FieldX='aaa'An exception happens. Now I need to attempt to determine what went wrong:1. Cable was cut2. Syntax error in SQL3. PC where SQL Server is running crashed4. Timed outI need to attempt to recover from this issue. I have basically 2 options: It is a glitch that self corrects after a period of time, so I can just go ahead and retry the operation a few times. Option 2: It is something permanent, so no matter how many times I retry, the error will persist.
View 3 RepliesI am currently programming in Visual Studio 2010 within VB.NET and am using DevExpress v10.2, specifically WinForms. In the DevExpress GridControl at runtime you can click on the right side of the column header and choose which values in the column you want to show. For example if your table contained:
Name1 Checked
Name2 Unchecked
Name3 Unchecked
Name4 Checked
Then if you click on the right side of the checkbox's header you can choose checked (or unchecked) and it would display only the data that is checked (or unchecked). In this case with checked you would have:
Name1 Checked
Name4 Checked
I was wondering if there was some way to override the names so instead of letting me choose checked or unchecked I could override it with 'owned' and 'rented' or 'active' and 'inactive' based on what the checkbox represents in that specific column.
I am currently using DevExpress 10.2 within Visual Studio 2010. I am printing the contents of the GridControl (with both one and two GridViews contained within). This shows all the current visible columns (and not the invisible columns) and all the data in a viewable manner.
My issue is the print preview always shows all the grouped rows and the master-detail rows fully expanded. I want to make it so that if the user has none of the groups or rows expanded then the print preview displays the grid with none of the groups or rows expanded. Also if the user expands the first group and rows fully then only the first group and rows will be expanded in the print preview and none other.
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I am currently programming within Visual Studio 2010 using VB.Net and DevExpress V10.2 Winforms. I currently have a DevExpress GridControl that contains two DevExpress GridViews.So there is the main view and the subgrid (similar to the DevExpress demo for Master-Detail Grids - example with WinForms and better view with ASPxGridView). Currently the data for the grid is fetched into a DataSet:
If myDataSet.Tables.Count > 0 Then
myDataSet.Relations.Add("Details", myDataSet.Tables(0).Columns("id"), myDataSet.Tables(1).Columns("id"))
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I currently have a DevExpress GridControl where one of the columns have a GridLookUpEdit assigned under ColumnEdit. Yet when I run there is a column name (the display member) that shows up.I know with a LookUpEdit you can set the column headers to invisible with lookupedit.Properties.ShowHeader = False but I have no clue how to make it invisible for the GridLookUpEdit.
View 3 RepliesHow to check whether a column is null i use the following code but I got this error "Input string was not in a correct format."
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When I put a break point to the last if clause in the sub ("If (backOrder < 0) Then", see below) it runs until the break point, if I put the break point further below, I get the following error:
Cannot insert the value NULL into column 'OrderID', table 'WHM.dbo.OrderDetails'; column does not allow nulls. INSERT fails. The statement has been terminated.
I've discovered first hand that it only happens when prodqty is bigger then qtyOnStock, thus executing the if clause.
The code:
Private Sub NCOSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NCOSubmit.Click
Dim sqlText As String = ""
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I am trying to create a treeview in VB.net, the data has to be loaded from MSAccess 2010 database. When I try to run this program I get error : Argument Null Exception was unhandled, 'column' argument cannot be null and the program crashes. I have pasted the code as under:
Imports System.Data.OleDb
Public Class frmRating
Private Sub frmRating_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles
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How would I get my program to let the user add a resource at runtime?
View 2 Repliesi've been searching for a way to delay a part of my program to let another part load, all i have found is threading sleep and one way which uses huge amounts of processing power. does anyone know a simple way to pause a part of script for a couple of seconds and then letting it run again? ( the problem is i need to get values from core temp, i also need to open it in the program. at the moment it say's "Object reference not set to an instance of an object." because it hasn't loaded by the time it is tried to be accessed. )
View 8 Repliesi'm working with a database application and i want to check if there is a null value in a specific column but it works only when its not null but if its null it throws an exception automatically
i tried to change the nullvalue property of this column but i'm not able it shows a message that its not a valid property
i tried to change the source code in the code editer but it changes back automatically
I have a databound DataGridView and use a button to control updates.
The problem is that if a db Column does not allow a null value an error is thrown ("Column <ID> does not allow null values") and then the datagridview automatically removes the row. This error is raised as soon as the user leaves the cell and before the update command is issued.
I have a date field (smalldatetime) in a table and in particular cases I need to set the date field to null. Currently, when setting the sqlparameter.value property to a date
endDateParam.Value = "5/15/2011"
the field is updated with the proper date. However, setting it to
endDateParam.Value = System.DbNull.Value
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I'm working with a database application and i want to check if there is a null value in a specific column but it works only when its not null but if its null it throws an exception automatically. I tried to change the null value property of this column but I'm not able it shows a message that its not a valid property. I tried to change the source code in the code editor but it changes back automatically. Is there a way that I can work around this?
View 5 RepliesUsing VS2005, VB.Net, Dot Net 2.0, SQL Server 2000. If have some Columns (varchar and numbers) in a DataRow that I want to set to DBNull in the database. The fields as defined as Nullable in SQL DB table.
I have some fields that are populated when loaded but I want to update to be null using the ADO.Net data objects. If I try and use Row("FieldName") = DBNull.Value a 0 gets written to number fields (not sure what gets written to varchar fields.) What code should be used to update fields to Null using ADO.Net dataobjects?
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I want to be able to create the checkbox control object in a gridcontrol and place it in every cell in a column because it has the functionality
I need with optional text built into the control. Does anyone know how to do this using vb.net, not C#.
I've using binding source filter to filter the data i see in the datagrid based on the value of the cell (this is in relation to the checkstate of a checkbox column), so far so good
InvBindingSource.Filter = "Saved = '1'"
what if i wanted to filter and only show the rows with null in that column?
I am selecting the max value of a column from a table. If the table does not have any rows i need the result as zero. how can i achieve this
View 6 RepliesI am currently working on an SSIS package that we are migrating from SSIS 2005 to SSIS 2008. The issue is that the developers of the current version used the fact that in SSIS 2005 the accessor of a NULL column returns 0, whereas SSIS 2008 throws an exception. Also, they extensively use expressions such as this one:
IIf(Row.X_IsNull, System.DBNull.Value, Row.X)
The problem is that in SSIS 2008, regardless of whether the condition is set to true, the program still tries to read Row.X and throws an exception. The package is big and it would take a very long time to convert all of these IIfs to manual Ifs with temporary variables.
With a Decimal, I use:
document.Air1 = CDec(IIf(Decimal.TryParse(Air1TextBox.Text, Nothing), Air1TextBox.Text, "0")) to fill the column with there is no value.
I would like to do something similar when the date is blank (preferably with NULL or just plain blank):
document.TestDate1 = CDate(IIf(Date.TryParse(TestDate1TextBox.Text, Nothing), TestDate1TextBox.Text, " - - ")) - of course, this throws an exception.
The table Data Type is date.
I am connected to a MYSQL database and the following Insertcommand works fine:
InsertCommand="INSERT INTO suppliers (Supplier) VALUES (?Supplier)"
Now when I want the option of updating all the columns it keeps saying "Column 'Contact_2' cannot be null" or contact_1, so all the fields need something and not all suppliers of course have two numbers. What am I doing wrong? here is the
InsertCommand="INSERT INTO suppliers (Supplier, Contact_1, Contact_2) VALUES (?Supplier, ?Contact_1, ?Contact_2)"
I have a smalldatetime column in SQL that can have a null value, but when I try to insert a null value using SqlTypes.SqlDateTime.Null and LINQtoSQL it puts in 1/1/1900 instead of NULL.
What is the best method to insert a null, or am I doing it at the moment. If I am using the correct method at the moment, what should be done to prevent the 1/1/1900 being displayed on my fields in a WPF application.
vb.net 2005
Here is one attempt:
Dim myRow As BurnerService.OEBSContractBatchesRow
Dim myDate As Nullable(Of DateTime)
myRow = Me.BurnerService.OEBSContractBatches.AddOEBSContractBatchesRow( _
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I am using DevExpress GridControl to display information from my database through a stored procedure (ie. SELECT * FROM aTable). Unfortunately when I run the program it doesn't display any of the information, columns, etc. It displays an empty table. I know that there is information contained by the GridView though as I have print statements that return the row count. Specifically:Console.WriteLine(GridView2.RowCount) ' returns the number of rows that should be displayedConsole.WriteLine(myTable.Rows.Count) ' returns the number of rows that should be displayedWhat should I do so that the actual data within the table (DataTable) and the DataView is displayed to the user. I know the row count is correct as when I add/remove a record the row count correlates by incrementing/decrementing.
View 1 RepliesI need to sort a DataTable or DataGridView by a column that is a string value, but with null/empty values at the BOTTOM when sorting ASCENDING. The DataTable is NOT populated by a SQL statement, so no order by. If I do
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I have a database and I'm storing images in it along with a person's name, and other attributes. I've databound my listview with a stored procedure. I want to know how I can display an icon on a row depending on if the record for that row has a picture or not for the person...I'm not sure how to accomplish this however with the templates in asp.net
EDIT:
Here is my template and the s where I'm hoping to put them.
<ItemTemplate>
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I need to sort a DataTable or DataGridView by a column that is a string value, but with null/empty values at the BOTTOM when sorting ASCENDING.The DataTable is NOT populated by a SQL statement, so no order by.If I doDataGridView1.Sort(New RowComparer(System.ComponentModel.ListSortDirection.Ascending))then it throws an exception, saying that the DataGridView is DataBound, which is correct, but doesn't help me, and I want to keep it databound.
View 2 RepliesI have a databound DataGridView, and I'd like to keep one column in front, with a slightly smaller width than the default. The grid's AutoSizeColumnsMode property is set to Fill so that the columns fill out the entire grid. This makes the first column equally large as all others, which is why I need to set its width manually. The smaller column is the first one with the checkboxes. I have two grids that I need to do this with, and for some reason it works just fine with the first grid, but gives a null reference error on the second grid...
Here's the code for the first grid (working fine):
vb.net
Public Sub UpdateTodoGrid()
' Load todo items
todoGrid.DataSource = _TodoManager.LoadAll()
' Set backcolor
For Each row As DataGridViewRow In todoGrid.Rows
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As you can see, the code is exactly the same (except for not setting the BackColor of each row and not using the ReadOnly property*). When I run this code, it gives me a null reference error ("Object reference not set to an instance of an object.") on the line where I set the column's Width. Obviously 'col' is not Nothing (otherwise it would have errored before that line), and there's nothing else there that could be Nothing... I assume that something happens internally in the grid when you set the width of a column, and that there is a null reference there, but obviously I have no control over that.
The grid's are absolutely the same, as the second grid is just a 'copy' (meaning I copy/pasted it in the designer) of the first. So all their properties are equal. I thought maybe the ReadOnly properties were the problem, but I tried putting them in in the same way and the issue did not go away... The first grid is not ReadOnly (because the checkboxes need to be editable), but all rows except the first are, while the second grid is completely ReadOnly.
Using DevExpress 10.2 within Visual Studio 2008 with VB.Net I have created a single gridcontrol that contains two different gridviews. The gridviews are related using an id column. Basically if there are related details about a row in the first gridview then the user can click on the plus sign to see all the related details. When I have any row on the first gridview I am able to get the focused row. Yet when I have the focus on any of the rows in the second gridview I am unable to get the focused row or the content of the row.
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Is there any way to get the value in id from the focused inner gridview? Or at least figure out the parent row and grab the id value from there?