I am using a SelectedIndexChanged function for a combobox to update the content of my DataGridview item. I have the combobox data bound to keep track of it's currently selected record. However, when I changed the combobox index it updates the datagridview as if the selected value was the same. This means once I have selected a different index value in the combobox, I have to select it again to run the function with the proper value.
Am I missing something here? Do I need to call the check for the current datarow selected in the combobox before calling the SelectedIndexChanged function?
Sounds like the page life cycle issue, as the datagrid will be fired before the slected index change if its in the page load event. at which point the index wont have changed so the data will be the same.
Related
The function should be simple:
I select an item, which is added to a list, then i manage that item using the list.
As first try i put some buttons next to the listbox and it worked fine.
But the objective is to add two buttons in each row, so i replaced the listbox with a gridview.
What's the problem? The event SelectedIndexChanged of the ComboBox (which is used to add the item to the list) does trigger once but not the second time.
The page correctly goes through page load, but the combobox's event is ignored.
Code here:
https://pastebin.com/Bmg2qjTf
I think i must say the combobox is filled using an SQL: the first time the SQL Query is executed and applied to the ComboBox's DataSource and in a Session, on PostBacks instead it gets refilled thru the Session variable.
Solution: Adding a txtNumSpedizione.Text = "";
Troubleshooting:
I tried to make both (listbox and gridview) work at the same time and this way it worked, also the gridview was getting all the selections.
So i figured out the difference between before and after was in the Text field "reset".
I have a weird problem with ComboBox Column in DataGridView in WinForm.
When I select the item from ComboBox, the selected value would not be rendered by the ComboBox. I need to click the ComboBox so that the selected value of the ComboBox would be rendered or displayed. If not, the ComboBox would just display empty.
The weird thing is this only happen in my first ComboBox Column in DataGridView.
In other words, this issue is not happening with my Second, Third or etc ComboBox Column in DataGridView.
Any ideas? Could it be a DataGridView bugs?
Thanks for your attention.
Thanks for your attention.
I manage to find the solution for the question that I have asked.
Overview:
I populate rows in DataGridView manually by adding row into DataGridView.
For DataGridViewComboBoxCell object, I use DataSource to populate the Items instead of adding the Items manually to the
ComboBoxCell.
The Problem:
Whenever you select the item in ComboBox, it is unable to render the selected value in the ComboBox. It would only show the value if you click it.
Solution:
It turns out in the code somewhere after I set the DataSource of the DataGridViewComboBoxCell, I called its method, DataGridViewComboBoxCell.Items.Count. This is the source of the weird behaviour.
Somehow, if you have set the ComboBoxCell DataSource, and you call Items.Count method, it would show that weird behaviour.
I should not use Items.Count since I am using DataSource. The Items.Count would always be zero because the DataBinding it's not happened instantly the moment you set the DataSource.
Hopefully this post would help someone else in the future. Thanks.
I am working on a master/detail gridview and detailsview in asp.net web forms using an objectdatasource. The details view is displaying extra information about the selected row from the gridview. When I sort the grid, I want the currently selected row, before sort occurs, to remain in the details view after the sort is completed. Instead, the gridview is auto selecting the new first row whenever I sort.
I found a partial solution to this problem. If I set WhateverGridview.SelectedIndex= -1 onsort and the value becomes null. This makes it deselect any rows after a sort. This leaves the details view blank. However, what I want to do is maintain the selected row not nullify it.
So, does anyone have a good way to retain the selected value or prevent the details view from displaying after sort event fires.
Here you need to use the GridView.EnablePersistedSelection property. Set this property to true.
Setting this property to true means that GridView will make sure that the selection of a row is based on data-key values.
By default GridView makes row selections based on index. This is the reason why when you sort, gridview is selecting row based on index and you lose your actual selected row.
I've got a bit of an chicken and an egg.
I need to bind a gridview to a set of database values. The gridview is dynamic and the columns, cells are created at run time.
As such, I need to re-bind the grid on every postback in the pre-init, init events after very post back.
However, the data used to populate the grid uses a value from a dropdown box on the same page. As such, the value of dropdown is not accessible through viewstate until after the init event (i.e. the selected index is always the first item in the list until after on init).
How can I get access to the value of the drop down in time to rebind the grid before the pageload event?
If the Gridview always has the same number of columns, you could have the dynamic query generate column names as aliases, and then just rebind the Gridview on dropdown change?
you can use and HtmlHidden control for store the value you need. It doesn't depend by the viewstate and it's available into the page init
I have a typical requirement.
I have a datagridview with a combobox column(items loaded at design time). When a user selects an item from combobox, remaining rows gets updated in database based on the selectedItem and dgv gets refreshed.
Problem is the combo box will lose its current selection and goes to unselected state.
I want to retain the selected item even after dgv refreshed.
Could anyone help me out
Thanks in advance
Do you mean that you're using an unbound comboboxcolumn? If so, the value can't automatically be persisted when refreshing the datasource. You need to store the selected value before updating and setting it in code after refresh.
If your column is actually databound, the selected value is either not stored in the database or you have some data type problem.
Is the combobox there to let the user select a value for the field or do you use it as a way to execute a command on the record?
Do you have any code you can post?
Datagrid Combo-Box value will retain the string value but will refresh any integer values automatically.
Here is what you need to do :
-When populating Combo-Box value to just convert its value to toString().
-Also if you are setting a default select value also set it with string type.
-Your Combo-box will automatically retain the value selected even after refreshing.
:)
have a combobox in ur datagridview. Assign values to it using a bindingsource.
then write an eventhandler for the datagridviews "EditingControlShowing" event.
in that, remove had handler if any exists for the comboboxes Selectedindexchanged event. then add an event handler for the selectedIndexChanged event say "ComboBoxValueChanged"
in that "ComboBoxValueChanged",
DirectCast the sender to System.Windows.Forms.DataGridViewComboBoxEditingControl and get the selected value of it.
Now use it to compute any value you want.
you may wana refer to this
http://msdn.microsoft.com/en-us/library/system.windows.forms.datagridviewcomboboxeditingcontrol.aspx