Alright, I am trying to accomplish this: When a user clicks a button that is on a ascx web user control with text boses, it first displays a DIV that is hidden, this div contains a ascx web user control. Basically I want that web user control to grab what they typed in the boxes on the first web user control, and then apply to a SQL search from what the users type in the text boxes on the first page. Is this possible or do I need to rethink my strategy on this? I am programming in c# for the SQL statements.
It is possible.
You can define properties of the control which accepts the text input, and expose the values using direct field access, variables, or session variables; you can then use FindControl from within the newly displayed control, and, if found, utilise the now exposed properties to gather the values required.
For instance, your input control code-behind might look something like this:
partial class MyControl : UserControl
{
public string MyFieldValue
{
get { return MyFieldTextBox.Text; }
}
}
And in the next control, to use it, a little like this:
partial class MyControl : UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
var myControl = Page.FindControl("MyControlInstanceName") as MyControl;
if (myControl != null)
{
var myFieldValue = myControl.MyFieldValue;
}
}
}
Is the 2nd user control embedded in the 1st or not?
If not, you can make anything available upwards between user controls by simply adding public properties to your user controls. This means they can then be accessed from the page level or the containing user control. For example, if I have UCA, UCB, UCC
UCA contains UCB and UCC is hidden.
UCB has the following property
public string UserEnteredName
{
get { return NameTextBox.Text; }
}
UCC has the following property and method
public string UserEnteredName { get; set; }
public BindResults()
{
UserEnteredLiteral.Text = UserEnteredName;
}
Then tie it together with UCA:
protected MyButton_Click(object sender, EventArgs e)
{
UCC.UserEnteredName = UCB.UserEnteredName;
... some logic herre.
UCC.BindResults();
}
You can also raise an event from UCB that can be responded to in UCA if your button or submit action exists in UCB.
Related
I am trying to develop a program in which it could create forms and add controls to it at runtime.
It also should be able to save, (Open and Edit) the forms created with the new controls added it at Runtime.The Application starts In the Main form.
CODE BEHIND MAIN Form
private void Btn_CREATE_FORM_Click(object sender, EventArgs e)
{
Form_Properties fp = new Form_Properties();
fp.Show();
}
private void BTn_ADD_BTN_Click(object sender, EventArgs e)
{
/// WHAT CODE SHOULD I ENTER TO ADD BUTON TO NEW FORM
}
Basically the main form is used to create/open/save new forms and add controls to it.
When the user clicks on Create New Form button the user will be presented with the following form (FORM_PROPERTIES) in which the user can customize the name, width and height of the new form.
CODE BEHIND FORM_PROPERTIES Form
public partial class Form_Properties : Form
{
public Form_Properties()
{
InitializeComponent();
}
String form_name;
int form_width;
int form_height;
private void Btn_OK_Click(object sender, EventArgs e)
{
form_name = TBox_NAME.Text;
form_width = Convert.ToInt32(TBox_WIDTH.Text);
form_height = Convert.ToInt32(TBox_HEIGHT.Text);
New_Form nf = new New_Form();
nf.Text = form_name;
nf.Width = form_width;
nf.Height = form_height;
nf.Show();
}
}
The following image shows what happens at runtime based on the code I have written so far.
ISSUES
Need help to Write Code
To add controls to new form created.
To Save/Open/Edit Functionalities.
I also need to know the method to access properties of added controls at runtime.
eg: If the user adds a text box to the NEW FORM and decides to type some text in it, I need a method to save that text.
Is there a way for me to name the added controls?
It seems you want to build some kind of WinForms' form designer. Your program would be similar to Glade (though Glade is much more powerful).
I'm afraid the question is too broad, though. There are many questions to answer, for example, how do you describe the created interface.
While Glade uses XML, you can choose another format, such as JSON. Let's say that you have a TextBox with the word "example" inside it.
{ type:"textbox" text:"example" }
It seems you want to add your components to the form as in a stack. Maybe you could add its position. For example, a form containing a label
("data"), a textbox ("example"), and a button ("ok"), would be:
{
{ pos:0, type:"label", text:"data" },
{ pos:1, type:"textbox", text:"example" },
{ pos:2, type:"button", text:"ok" },
}
But this is just a representation. You need to a) store this when the form is saved, and b) load it back when the form is loaded.
For that, you will need a class representing the components, such as:
public class Component {
public override string ToString()
{
return string.Format( "position:{0}, text:{1}", this.Position, this.Text );
}
public int Position { get; set; }
public string Text { get; set; }
}
public class TextBoxComponent: Component {
public override string ToString()
{
return base.ToString() + "type:\"textbox\"";
}
}
...and so on. This is a big task, I'm afraid, with no simple answer.
I'm approaching to Metro App world in this days, please be gentle.
Here's the problem:
a page receives a string from another page
protected override void OnNavigatedTo(NavigationEventArgs e)
{
Title.Text = e.Parameter.ToString();
}
and I need to pass this string to an User Control of the receiving page.
How can I pass a parameter from a page to an UserControl of another page?
Like this:
Add a property to your user control:
public string MyText { get; set; }
Give your user control a name.
<src:TopBarControl x:Name="MyTopBarControl" />
Then use your NavigatedTo method:
protected override void OnNavigatedTo(NavigationEventArgs e)
{
var _TextParam = e.Parameter.ToString();
this.MyTopBarControl.MyText = _TextParam;
}
This will feed your User Control what it needs.
You could also bind to it by setting the parameter to some public property of the page. If you attempt this approach, please remember to make the User Control's property a Dependency property and not a CLR property. I wrote an article on binding if you want a better explaination http://blog.jerrynixon.com/2012/10/xaml-binding-basics-101.html
Best of luck!
Assuming usercontrol is part of navigated page, you have to do set Property of User Control on OnNavigatedTo override.
Example:
class MyUserControl : UserControl
{
public object Parameter {get;set;}
}
Suppose this user control is part of MyPage
class MyPage : Page
{
private MyUserControl myUserControl; // It is only for illustrations, Otherwise it goes to .designer.cs
protected override void OnNavigatedTo(NavigationEventArgs e)
{
Title.Text = e.Parameter.ToString();
myUserControl.Parameter = e.Parameter; // This is how to set the parameter in usercontrol.
}
}
I am working on an ASP .net project. I am trying to load a user control in a Control object with the following code and i am trying to pass a parameter to that control. On the debugging mode I get an error on that line saying that The file '/mainScreen.ascx?matchID=2' does not exist.. If I remove the parameters then it works ok. Can anyone help me to pass those parameters? Any suggestions?
Control CurrentControl = Page.LoadControl("mainScreen.ascx?matchID=2");
You cannot pass the parameter via query-string notation because user controls are simply "a building blocks" referenced by virtual path.
What you can do instead is to make a public property and assign the value to it once the control is loaded:
public class mainScreen: UserControl
{
public int matchID { get; set; }
}
// ...
mainScreen CurrentControl = (mainScreen)Page.LoadControl("mainScreen.ascx");
CurrentControl.matchID = 2;
You can now use the matchID inside your user control like the following:
private void Page_Load(object sender, EventArgs e)
{
int id = this.matchID;
// Load control data
}
Note that the the control is participating in the page life cycle only if it's added into the page tree:
Page.Controls.Add(CurrentControl); // Now the "Page_Load" method will be called
Hope this helps.
How can I pass user control properties to the page AND make these properties available to all methods on the page (and not just to one method that is fired on a control action, e.g. onControlClick)
I have a set up of essentially 3 pages:
user control (ascx/cs)
class (cs) - that contains user control properties
host page (aspx/cs) - references the user control
The user control consists of 3 interrelated dropdowns. I'm having success passing these dropdown values through a class onto the page via an event that is fired when a user clicks on the dropdown menu. So this way the host page is continously aware of the values in the user control. However, I want the page to use the control's properties (stored in a class) on all of its methods - how do I make this user control class available to all?
Also I'm using ASP.NET and C# by the way.
Here's the Code (not sharing the full code here - just the snippets of a similar code block)
On the ASPX for Menu Host Page:
<linked:LinkMenu2 id="Menu1" runat="server" OnLinkClicked="LinkClicked" />
Host Page (cs):
protected void dropdownclicked(object sender, ddtestEventArgs e)
{
if (e.Url == "Menu2Host.aspx?product=Furniture")
{
lblClick.Text = "This link is not allowed.";
e.Cancel = true;
}
else
{
// Allow the redirect, and don't make any changes to the URL.
}
}
Host Page (aspx)
<asp:dropdowncustom ID="dddone" runat="server" OnddAppClicked="dropdownclicked" />
Control (cs)
public partial class usercontrol_tests_dropdown1 : System.Web.UI.UserControl
{
public event ddtestEventHandler ddAppClicked;
}
public void selectapp_SelectedIndexChanged(object sender, EventArgs e)
{
ddtestEventArgs args = new ddtestEventArgs(selectlink.SelectedValue);
ddAppClicked(this, args);
}
Class:
public class ddtestEventArgs : EventArgs
{
// Link
private string link;
public string Link
{
get { return link; }
set { link = value; }
}
public ddtestEventArgs(string link)
{
Link = link;
}
}
public delegate void ddtestEventHandler(object sender, ddtestEventArgs e);
Hopefully this is what you're after. The best way to do it is to expose your controls as public properties from your user control. So, in your user control, for each drop down list add a property:
public DropDownList DropDown1
{
get { return dropDownList1; }
}
public DropDownList DropDown2
{
get { return dropDownList2; }
}
You can do the same for any other properties you want to access on the host page:
public string DropDown1SelectedValue
{
get { return dropDownList1.SelectedValue; }
set { dropDownList1.SelectedValue = value; }
}
Then, from your host page you can access the properties through the user control:
string value = UserControl1.DropDown1SelectedValue;
or
string value = UserControl1.DropDownList1.SelectedValue;
Here's a couple of other answered questions that you might find useful as I think (if I've understood correctly) this is what you're doing:
Getting data from child controls loaded programmatically
How to change the value of a control in a MasterPage.
I am just getting to grips with the concept of a UserControl.
I've created a UserControl to group together a number of controls that were being duplicated on individual pages of a TabControl.
Some of these controls are text fields that require validation, and when validation is unsuccessful I need to display an error message. However the place where I want to display the error message is on the status bar on the main form.
What is the best way to handle validation/error display in this situation?
To handle validation do one of these:
Validate with a method inside the user control
Have your user control have a delegate property (e.g. ValidationHandler) that can handle the validation (this would allow you to have a class with a bunch of validators that you could assign to your controls)
public delegate void Validator(...)
public Validator ValidationHandler { get; set; }
Have your user control generate a validation request event (e.g. ValidationRequested)
public event EventHandler<ValidationEventArgs> ValidationRequested
To notify the system that an error has occurred do one of these:
Use an event that interested parties can subscribe to (e.g. ValidationFailed)
If the object that performs the validation (via the delegate or event) is also the one that you want to generate the error message from, it can raise the error message itself.
EDIT:
Since you've said you would validate inside your control, the code for a ValidationFailed event might look like:
// In your user control
public class ValidationFailedEventArgs : EventArgs
{
public ValidationFailedEventArgs(string message)
{
this.Message = message;
}
public string Message { get; set; }
}
private EventHandler<ValidationFailedEventArgs> _validationFailed;
public event EventHandler<ValidationFailedEventArgs> ValidationFailed
{
add { _validationFailed += value; }
remove { _validationFailed -= value; }
}
protected void OnValidationFailed(ValidationFailedEventArgs e)
{
if(_validationFailed != null)
_validationFailed(this, e);
}
private void YourValidator()
{
if(!valid)
{
ValidationFailedEventArgs args =
new ValidationFailedEventArgs("Your Message");
OnValidationFailed(args);
}
}
// In your main form:
userControl.ValidationFailed +=
new EventHandler<ValidationFailedEventArgs>(userControl_ValidationFailed);
// ...
private void userControl_ValidationFailed(object sender,
ValidationFailedEventArgs e)
{
statusBar.Text = e.Message;
}
If you're doing the validation in the UserControl, you can have it offer a public ValidationFailed event and include the message in the EventArgs. The parent control could then subscribe to the ValidationFailed event and update the status bar.
You can either put a validator on the user control itself, throw an exception, or add public getters to the fields you want shown in the parent form.
Make a public method on your usercontrol that validates its field, and you can pass in a string output parameter.
so something like
public bool IsValid(out string status)
{
// do validation and set the status message
}
You can use asp.net validators in the user controls, and a validation summary on the main form and it will list the errors for you.
For other type of uses, you can expose an event, and have the page that contains the control subscribe to the event and take whatever action necessary.