I have a gridview. Its datasource is set as follows.dtTable is a datable in which the values for the table will be retrieved. But when setting dtTable as datasource I get an error "Object reference not set to an instance of an object". What may be the reason for this?
gridview.Datasource = dtTable
gridview.Databind()
I currently have a control that called MyGridview that inherits Gridview. It has a paging template within it for customized paging options, and I'm at the point where I want to cache the initial datasource for better performance.I haven't done this in a long time, so perhaps there is a different solution these days with the newer frameworks.Before, I simply used a Cache object that was named whatever the gridview was named. I couldn't use the same gridview name through the application though.Is there a best way to have a cache object, or some other object like a session within the control to store those unique datasets for paging and sorting?
View 1 RepliesI have a gridview that I would like to be able to bind to several sqldatasources, but still use template fields. Each datasource is different and would have different columns so I'm not sure how to go about this. Is it possible to define a set of template fields or overlying template per datasource?
View 2 RepliesI am kind of an old 'newbee' at this, so bear with me for a moment. I am developing a windows forms application in Visual Studio 2010 Professional that connects to a remote database (MS sqlServer 2008 R2).To speed up development, I configured a DataSource and used the data objects associated with it. In VB6,
the data source could be assigned to the data objects during runtime using a variety of different runtime database connections, ODBC, ADO, ...
I have been unable to find a similar method with the VS2010 Visual Basic DataSource and underlying TableAdapter, BindingSource, BindingNavigator, down to the individual ComboBox and assorted other bound controls. It's convenient to have the integration, but I've got different users with different permissions, The long and short is that I'd like to be able to assign the data source during runtime operation, at least to the connection string level.
My current problem is this:I have a form and I have in it three textboxes, 1 button and 1 datagridview; I also have an acceI'm learnig now on how to create a report without a database. But In how to set the datagriview as the datasource for my report
View 8 RepliesI want to maintain a list of potential ComboBox values over multiple executions of my program, and to use that list as the DataSource on multiple ComboBoxes. I also want changes made to the DataSource to propagate over all of the ComboBoxes already existing in the application.
Can someone recommend what type of object I should use as my DataSource, as My.Settings objects don't seem to support generic list objects.
Also, along with that recommendation, can I also ask for suggestions as to how to propagate the updates of the collection to all ComboBoxes? I would imagine I need a collection type which raises events when its contents change, but I can't think of any, and in any case do not know which are compatible with My.Settings.
I have a GridView on an ASP.NET page that I'm trying to bind to an object data source that I've set up to map to a vb object I made which accesses the DB. When I run the page, though, the gridview comes up empty.
The ObjectDataSource is definitely returning data. The paging parameters are making it to the underlying object. All the way until I get to the DataBind() call everything seems fine. But the grid comes up empty. Funny thing is, if I use the method that returns all records in the DB, the grid populates just fine. Only when I try to implement custom paging does display no records. I've tried using the wizards, I've tried diagrammatically setting it up and run time. No matter what I do I can't get paged data to display in the grid.
oDatasource = New ObjectDataSource()
oDatasource.EnablePaging = True
oDatasource.TypeName = "tblMessage"
oDatasource.SelectMethod = "GetTblMessageSubset"
[code]....
Suppose a click event is fired and a particular gridview datasource is set in the code behind page by retrieving a data table from a business logic class.
So programmatically speaking, what is the main difference between the two set of code listed below.
CODE:
I guess my main question is, what is the purpose of creating a new instance of an object in the above scenario?
I am using VB.net.
I have a gridview with a datatable datasource.
What is the best option to update the datatable when i delete a row in the gridview and then show the gridview without that row?
I have a small requirement and that is as follows:
I am populating a ListBox using stored procedures and the ListBox is populated as follows:
lstItems.DisplayMember = "emp_name"
lstItems.ValueMember = "login_id"
lstItems.DataSource = accessFunction.getEmployees
The ListBox gets populated correctly. After it is populated, i have a CommandButton and on the click event of the button, i want to remove selected items from the ListBox. So in the click event of the CommandButton, i have written the following code:
lstItems.Items.Remove(lstItems.SelectedItem)
After selecting an item from the ListBox and when i click the CommandButton, i get an error as "Items collection cannot be modified when the DataSource property is set".
how i can delete items from the ListBox.
[code]My question is how can I remove xStopBits(0) before setting the DataSource?To get around this I currently have a check in the ComboBox1_SelectedIndexChanged event.
View 14 RepliesI have a datagridview that is populated using an oledbconnection:
Private Sub FileSpecs_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim cn As OleDbConnection = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & My.Settings.DBLocation & ";")Dim cmd As OleDbCommand = New OleDbCommand("SELECT specFieldno AS [Field No],specFieldName AS [Field Name], specFieldType FROM fileSpecs WHERE ClientNo='" & ClientSetup.clientNo.Text & "' AND direction=" & ClientSetup.fileDir, cn)
[Code]...
The problem I now face is that the 'index' value of the combobox item for each row is in the field specFieldType which is populated into the datagrid.I need to be able to set the value of the ComboBox for each row when the form is opened, and also be able to save the index value of each row selection if any changes are made/saved.
I am stuck at a task. What I want is, I am creating a table in the database on the fly in the code behind using the below code(in VB).Now my main problem is I want to display this table which is created in step 2 of a wizard, in step 3 using a GRIDVIEW. But as we all know a GridView needs a sqldatasource for values to be displayed, however what I need for achieving this is dynamically assign a datasource to the GridView, but I am not figuring out HOW?
Dim NewTable As String
Dim FullName2 As String = "Dynamic" + "_" + lblCompanyName.Text + "_" + tbCustomerFileName.Text
'Get Row Headers and map to Fields
readerXML.ReadHeaders()
[code].....
If I used a generic list Class to hold data objects that I am pulling from SQL Server using Linq to sql to populate a datagridview would I need to make any modifications to the datagridview control to accomodate multiple columns or would I need to make any modifications to the generic list class to accomodate the multiple columns in a row that is typical of a record in SQL Server? And one more thing which I believe is the easy part. To bind the list to a datagrid view would I just use the datasource property of the datagridview control.
View 2 RepliesI have a gridview that is bound to a datasource (Windows Forms, VB.NET). One of columns is a property of type boolean, and I want to show "yes/no" in the column instead of 0/1 or "true/false". Is this possible? Can you edit displays of columns that are bound?
View 1 RepliesBelow is my gridview sample that retrieve a formatted html in my database..All i want to achieve is to limit the maximum length of characters i.e "50" then automatically create a pagination for the succeeding characters..to be posted in the gridview
<div id="GridScroll" class="grid_scroll">
<asp:GridView ID="GridView2" runat="server" AutoGenerateColumns="False" BorderStyle="None"
GridLines="None"
[code].....
I've been searching for quite a long time how to do this. I don't know how to set the colour of a row item in the GridView (WPF) using code I don't want an example in XAML. My data comes from me loading & pulling apart an XML file. I then put it into a small class with properties and those are bound to the column to populate the data. Later, it can begin some functions on the table's data. Because this takes at some times over 10 minutes it's on a thread & I would like to colour the rows I've completed parsing depending on the result. (IE: Red for HTTP error, Orange for XML parsing error ect...)This is the GridView's XAML:[code].....
I am then parsing the data using the url column. I am currently changing the selected item as I go through. I want to know if theres something I can do to change the specific item. Let's assume I'm on row 500: I use: setSelected(i) which uses Dispatcher to safely change the selected row. Is there anything I can do to change the colour as well?
I'm stuck trying to figure this one out. I am trying to set a GridViews Column properties by using reflection and the Extended properties off a DataTable.the Code looks something like this
Dim colproperty As PropertyInfo = gv.Columns(col.Ordinal).GetType.GetProperty(key)
Where key = "ItemStyle"
So I get the ItemStyle Property by I'm unsure how to set the next varibel which would be BackColor:Red in the collection i have that key access. This is all text.in the XML the extendedproperty is set like this
msprop:ItemStyle="BackColor:Red"
I can easily set all of the attribues for a gridview using something simular to this but of course gridview columns do not have attributes only properties.
Gridview attribute setting code
Dim nvCollection As PropertyCollection = table.ExtendedProperties
For Each key As String In nvCollection.Keys()
Dim colproperty As PropertyInfo = labelOut.GetType().GetProperty(key)
[code]....
Columns 0 & 1 are filled from a DataAdapter from Access Database and three are added. I had this working, but I changed it to check for the column "Feed" so I could add several Locations. At first this worked,but I did someething in perfecting it and it now fails after filling the first row of the datagridview (dgvFdMed).I ran a check and the table LotsTab has 8 rows filled. Column 1 & 2 are strings and the database appears they are fine. The added columns have just been created with no value. My plan is to enter the values and then use the data from the grid.
Private Sub sfillGrid(ByVal Loc As String)
Dim i As Integer
Dim column As DataGridViewColumn
[code]....
I have a datagridview bound to a datatable setting its datasource property to the datatable. I would like to have a child form that contains a list of columns associated with the datatable that contains a checkbox that will allow the user to hide and show the columns ( I do not know the best control to use here) (I assume this is the easy part as All i need to do is loop through each of the datatable's columns to get the column name)
now I would like save these visible columns on some event like form_closing so that the next time the user opens the form up it will remember the settings
i was wondering is there anyway to stop the error popup messages when i assign a datasource to a DataGridView (and there are errors). i was hoping i could wrap the assigning statement into a Try Catch and handle the errors myself instead of having them popup.
View 2 RepliesI created a master - detail form . I changed the name of one datacolumn in the dataset (not the source) from "alert_name" to "alert_name_new" and i saved all files.I checked the file <dataset>.xsd in the directory and i found the change was made... as expected.When i try to run the application the following error message appears: "Cannot bind to the property or column ALERT_NAME_NEW on the DataSource."
Note: I use vb 2010 express edition
I use vb.net and windows form and sqlserver
I added Data Source(Microsoft SQL Server (SqlClient)) to my project. and now I need to change it to ODBC Data Source .
I'm currently using a combo box in vb.net to select one of many alternatives. From 5 alternatives only 1 works, when i click on any other it gives me the following error:"Cannot bind to the property or column 'xyz' on the DataSource.Parameter name: dataMember" Why is this error caused?
View 14 RepliesI am setting a value in the registry like this[code]...
Problem is, if opensubkey would return nothing. Then .GetValue will throw an exception, obivously.[code]...
I'm using the following snippit of code to update an entry:
Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles button1.Click
With SqlDataSource1
[Code]....
I am trying to set a rich text box value with this
[Code]...
but it does not work...WHats wrong
I have a DataAccessLayer that returns a datatable. The business layer calling it also returns a type datatable.In my form, I call the business layer as a datasource of my gridview and then I binded it.
This codes are working in C# but I have problems when I converted it to VB.NET. During databind it displays the error: Data source is an invalid type. It must be either an IListSource, IEnumerable, or IDataSource.
Can i not bind a datatable in my gridview in vb.net? What do you think is the problem?
I have a gridview and have modified it following this article: url...to allow bulk updates. Whenever I try to update a row in this loop:[code]
View 1 RepliesI have this simple code,
Protected Sub grdSearch_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles grdSearch.SelectedIndexChanged
TimeOff.Where = "UserName=""" & grdSearch.SelectedValue & """"
End Sub
Doing so causes this error, 'UserName' could not be resolved in the current scope or context. Make sure that all referenced variables are in scope, that required schemas are loaded, and that namespaces are referenced correctly. Near simple identifier, line 6, column 1.
The datasource works fine before the where property is set.Update: I found the issue but I still don't get it.Adding it. in the where clause solves the issue. Like this,
TimeOff.Where = "it.UserName=""" & grdSearch.SelectedValue & """"