I have AspxGridView on my page. I want users to be able to set up some data on the web form, and after they press one button, the data from screen is being read, validated and bussines object is being created. This object has a GetData() function, and returns an array of objects representing rows in a grid.
I want ASPXGrid not to populate, until user clicks the button. I know I can set DataSourceId in design time to null – but then I lost availability of synchronizing grid columns with object properties (I cannot add or edit some column properties for new columns). I know I can intercept ObjectCreating event and provide grid with an fake object returning empty data sets. But are there any more elegant solutions?
When are you doing the DataBind() call? Couldn't you just place that inside an if block to make sure it only happens on postback?
if(Page.IsPostBack) {
DoDataBindingStuff();
}
Related
I don't know think I wrote any code for this since the properties are all default. I don't want the user to have to add those by themselves when it is in the middle of the run.
It lets me add in columns but not rows in the designer.
Is there any property that can start the program with more than 1 row in the data grid view?
Populating the grid with data must be done with code. If you populate the grid in the Load event handler then the user will see that data when the form is displayed. You can add data directly to the grid or you can populate a DataTable or some other list and bind that to the grid.
If you're saying that you actually want multiple blank rows in the grid then you need to add those rows. The row you see by default is not actually part of the data of the grid. It's just there to indicate to the user that they can enter data.
I have a class (let's call it Object) that contains an ID and some other data. I want to display the IDs in a gridview. When the user clicks on an ID in the gridview table, I want the ability to add code that accesses the object of the ID and display the Object's details (it's ID and other stored data).
So far I've been able to store the data in a tabletable and set it as the gridview source, but I haven't been able to extend the click event feature.
Any ideas on how to implement this in C#?
The object used to load into the GridView is gone as soon as the page unloads. The contents are retained in viewstate, but the object is not there. What you need to do is query the data again using the selected ID. Or link the Grid to a DetailsView, which will query the data, as #Wahtever suggested in the comments.
I'm trying to create an ASP.NET/C# page that allows the user to edit a table of data, add rows to it, and save the data back to the database. For the table of data, I'm using a DataGrid whose cells contain TextBoxes or CheckBoxes. I have a button for adding rows (which works) and a button for saving the data. However, I'm quite stuck on two things:
The TextBoxes and CheckBoxes should retain their values on postback. So if the user edits a TextBox and clicks the button to add more rows, the edits should be retained when the page reloads. However, the edits should not be saved to the database at this point.
When the user clicks the save button, or anytime before, the DataTable underlying the DataGrid needs to be updated with the values of the TextBoxes and CheckBoxes so that the DataTable can be sent to the database. I have a method that does this, but I can't figure out when to call it.
Any help getting this to work, or suggestions of alternative user interfaces that would behave similarly, would be appreciated.
Take a look at the ASP.NET GridView control. It's newer than the DataGrid and has editing features, editing events, etc built in.
Check out the following website:
http://highoncoding.com/Categories/7_GridView_Control.aspx
There are tons of articles on the above link about the GridView control.
I have a simple app I am messing around with its a basic Master/Details layout.
The details panel is actually a tab panel and on one of the tab panels it has a GridView. Within that grid view it shows the "current" in database information with all cells as read only.
alt text http://lh4.ggpht.com/_JU1W2P96pD4/TAeonNNYXgI/AAAAAAAAAq0/Y_-Kse7VObE/ExampleA.jpg
I then have an add button that inserts a row into the GriView and allows the user to enter some information. The first item in my GridView is a DropDownList, which is populated from an ObjectDataSource. This drop down is basically my unique index and there can only be one selected value per GridView.
alt text http://lh3.ggpht.com/_JU1W2P96pD4/TAeonIF3DdI/AAAAAAAAAq4/JhfOTsHgsf8/ExampleWithDropDown.png
What is the best way to remove the values from the list that are already in the GridView? Do I just need to remove the data source and add a OnDataBinding method that iterates through the grid view and generates a valid list of values?
I can't use a service method because if the user adds two rows they would have the option to insert duplicates description types.
Just want to make sure there is not a better way to do this.
Keep the object datasource, which I am assuming is an IEnumerable object, in a Session variable. When someone selects a certain value remove that value from the list in the session variable. Whenever they activate the form where the drop down list is displayed simply rebind the control to the list in the session variable. It will be easier than looping through the grid every time the user adds an entry.
I have a TextBox entry field where the user will enter a integer value. And then there is a "Create" button, which when clicked upon must generate a Table with 2 columns :
"Name" and "Email" being the column headers.
I want each row to have a textbox in each of these columns.
All of this has to happen after the button is clicked. I have discovered that if you dynamically add a control in ASP.NET(I am using C#) then the controls are lost during postback. And I don't know how to prevent that from happening.
Can somebody please give me some ideas regarding how to go about adding rows dynamically to a table (I tried using the asp.net Server side table control but ran into the "lost-during-postback" problem - can I try with something else like a gridview ? but afaik a GV will not work without data bound to it )
Point to note is that my table has textboxes for user entry and it is not for showing data ..rather it is for accepting data from the user which will be later used to persist details to the database.
Dynamic Controls
That's involved. Here's an interesting article on the issue of dynamic controls.
I think normally if you create dynamic controls then you're responsible for recreating them on postback; however the article contains a way to use the Init event if it's copacetic with your app.
Edit:
or Regular ASP.NET Controls
You can use data bound ASP.NET controls like: DataList, Repeater, GridView, etc. (You can put text boxes and all other kinds of controls into them for repeating in each row - or "item") and bind values to it. If you need to perform some processing on the user input first, then generate an internal Array, List, Dictionary, DataTable etc. (your choice) and bind that data as a data source to the ASP.NET control of choice.
aspnetControl.DataSource = myDataTable;
aspnetControl.DataBind();
or
aspnetControl.DataSourceId = "name_of_control";
There are various ways to assign a data source.
This way you won't run into the same problems as with dynamic control creation; however there is a lot to learn to facilitate this way too.