I've a form that navigates webpage and access data. It looks like something below.
private void LoginButton_Click(object sender, EventArgs e)
{
if(LoginButton.Text == Login)
{
LoginButton.Text = "Logging in...";
....
...
Login process goes here...
..
if(Login Successed)
{
LoginButton.Text ="Download";
}
else
{
LoginButton.Text = "Login";
}
}
else if(LoginButton.Text==Download)
{
Download data here...
}
}
Same button(And same event too), doing two process and seems like different events with a label.
1) If there any problem like inefficiency run?
2) Any alternate ways to do this like different flag schemes?
3) Any method to have with more than one event for same button to achieve same idea?
Thanks.
1) If there any problem like inefficiency run?
Button clicks run at human time. You can burn half a billion cpu instructions without inconveniencing the user.
2) Any alternate ways to do this like different flag schemes?
Using the Text property of the button is fragile, your code will break when somebody decides to change the button text or when you localize your app to another language. A simple private bool field in your class is much better.
3) Any method to have with more than one event for same button to achieve same idea?
No. You could of course use two buttons, placed on top of each other and one of them always hidden. Makes localization much simpler and you'll get that bool field for free.
like Daniel A. White said
have two buttons
may be on some event like oncreate/onload do check..jst a pseudo code
if process is login then
do
//then showLoginButton
btnlogin.visible
else
//download
btndonload.visible
inside the login button
if(Login Successed)
{
btndonload.visible
}
else
{
LoginButton.Text = "Login";
}
this may be better with two buttons then single..and cleaner also
Write custom event handlers for the mouseClick
Write separate methods for login and download.
Register your custom event handlers to the button click event
I assume there is some logic that decides that the button text should be "download" or "login". At that point, set the button text of course, but also register the appropriate event handler.
This will allow you to have a single button that does anything
protected void Login_MouseClickHandler (object obj ,MouseClickEventArgs e) {
// login logic
// this would be the logic you say is "inside the login button"
}
protected void Download_MouseClickHandler (object obj ,MouseClickEventArgs e) {
// download logic
}
// pseudo code
// note that there is only one button
if process is login then
theButton.text = "login"
theButton.MouseClick += new MouseClickEventHandler(Login_MouseClickHandler)
else
button.text = "download"
theButton.MouseClick += new MouseClickEventHandler (Download_MouseClickHandler)
end if
Software Design Thoughts
Easier to extend. We don't need another button for every new thing to do
Separation of Concerns - All login code, for example, is in a separate method that does only login stuff.
Change is isolated and minimized. Writing new, separate methods is less error prone than in-lining that code in your if else structure. And consequently the if else structure is kept simple and comprehensible.
It is generally a bad idea use the text as the state. Ideally, you should have 2 buttons that fire different events and call out the main logic to a presenter in the MVP pattern.
Use control containers such as Panel and GroupBox. You can have a whole bunch of Panels for controls in different states.
Related
Here is what I have tried and is working. But I want to whether this is proper or is there a better option or way to do the same
private void tabs_SelectedIndexChanged(object sender, EventArgs e)
{
TabControl control = (TabControl)sender;
if(control.SelectedIndex == 3 || control.SelectedIndex == 0)
{
button1.Parent = control.SelectedTab;
zonalarealabel.Parent = control.SelectedTab;
pictureBox3.Parent = control.SelectedTab;
}
}
If you don't mind coupling your code to your user interface then your approach is valid. However, I think the better option is to create a user control that raises events handled by the selected tab. The user control would appear on tabs 0 and 3 at all times. The advantage of this is that you don't need to modify your SelectedIndexChanged event handler should you want these buttons to appear on a future tab. There are many ways to approach this problem, but given the very narrow functional requirements you shared, it's a better design to relegate these buttons to a user control rather than re-parent them at runtime.
Hi im hoping someone can assist im still new to programming and this is a noob question but i have created a Visual studio - C# (Windows Form Application) and now the question reads to Create a void method for each of my buttons i created in the form and telling me even what to name the method.
but on my research The void keyword is used in method signatures to declare a method that does not return a value.
LinkToAddresses () will be my void method for address the (button), so my question is do i just put in this void method and its going to do nothing?
im just going to link the full question maybe im just really not understanding this>?
''
The below form will represent the main form from which the user will navigate to the other forms. Meaning each button should be linked to the appropriate form. E.g. If button Manage Addresses is clicked the form managed addresses should be displayed. The Exit button should successfully terminate the program.
Create a void method for each button and name them as follow: LinkToAddresses (), LinkToCustomers (), LinkToDrivers (), LinkToStatus (), and LinkToFreight (). The methods should be called under the appropriate button. For the exit button create a void method named AppExit () this should terminate the program.
''
I would appreciate any help or guidance, thank you in advance.
Visual studio usually handles the button actions easily. Just place the buttons on your form, then rename the buttons to LinkToAddresses, LinkToCustomers, LinkToDrivers, LinkToStatus, LinkToFreight and AppExit. Then simply just double click on the each button and visual studio will create a void method for their click event.
using System;
using System.Windows.Forms;
namespace YourApp
{
public partial class FormMain : Form
{
private FormManagedAddresses formManagedAddresses = null;
public FormMain()
{
InitializeComponent();
}
private void LinkToAddresses_Click(object sender, EventArgs e)
{
if (formManagedAddresses != null)
{
formManagedAddresses.Close();
}
formManagedAddresses = new FormNews();
formManagedAddresses.Show();
}
private void AppExit_Click(object sender, EventArgs e)
{
Application.Exit();
}
}
}
The closest thing to a buttons function, is the Click Event Handler. While specific names vary based on Display technology (WinForms, WPF/UWP, ASP.Net), that is the general pattern for Graphical User Interfaces. It is called event driven programming. Even things that have a different programm flow like Games and Web Applications usually try to imitate it.
The signature of a event is given during its definition and must be strictly followed. Usually void NameOfTheEvent(object sender, SampleEventArgs e).
A return type of void is extremely common with events. If there is to be any output, that usually is handeled via a property in the Event Args or by directly doing stuff with the other GUI Elements.
If you want a button to do nothing, you just never give it a event handler. Every single button you ever used, was given a implicit or explicit event handler to do exactly what it did. If you want it to conditionally do nothing, either disable the Button so it can not be clicked, or put a proper if-statement into the event Handler.
A advanced topic would be the command pattern, where there is a bunch of commands in code behind. And each button, menu item and key combination is meerely a way to trigger said command - a representation for hte user to call the command.
You can share a single event across any number of Elements. AS you can see above, the pattern for events includes object sender as argument. This means you can check if it is a specific Button instance that called the event. Or even "unpack" the specific button, do look at stuff like Display String, Tag to get data from it. However, as a general rule retrieving data from the GUI is a bit frowned - ideally the GUI should only represent the data in the backend.
What is the best way to create and read multiple textboxes in a windows form? In my application, I have a windows form where customer can enter multiple addresses, email addresses
Right now I have a form like this,
TextBoxAddress1 TextBoxEmail1
TextBoxAddress2 TextBoxEmail2
.....
.....
.....
TextBoxAddressN TextBoxEmailN
For this I dragged and dropped multiple controls on a form and named each one of them.
If I use this method I had to write lengthy code to see if first row (TextBoxAddress1 TextBoxEmail1) is filled for validation and even for reading I had to write many lines of code.
Is there a better to way achieve this?
You can use the following code to add a TextBox dynamically to your form:
private int m_CurrTexboxYPos = 10;
private List<TextBox> m_TextBoxList = new List<TextBox>();
private void CreateCheckBox()
{
m_CurrTexboxYPos += 25;
TextBox textbox = new TextBox();
textbox.Location = new System.Drawing.Point(0, m_CurrTexboxYPos);
textbox.Size = new System.Drawing.Size(100,20);
Controls.Add(textbox);
m_TextBoxList.Add(textbox);
}
I would have a listbox/listview with your emails and Add/Edit/Delete buttons which show a popup form - the logic for validating emails, etc. would then be in the one place and your list can grow without you ever needing to add controls to the form.
You could dynamically create textboxes - but you end up writing code to make sure they layout nicely on the form, etc. - having some type of list is easier IMO and also lends itself to binding (e.g. to an email object)
Dynamically adding controls is pretty simple, provided you can use DockStyle and an exclusive container for them (e.g. a Panel). If you can't use DockStyle, then you need to write logic to determine Location and Size (which isn't fun).
On a simple form, I have two buttons and a panel, Button1 adds a new TextBox to Panel1, Button2 iterates through the controls in Panel1 and then checks that they are the correct type or throws an exception. This is where you you would put validation or reading logic. Panel1 needs to have AutoScroll = true; otherwise you will run controls off of the viewable screen.
This concept can be switched for anything that inherits from UserControl (all .Net native controls or your own custom controls).
private void button1_Click(object sender, EventArgs e)
{
TextBox NewEmailBox = new TextBox();
NewEmailBox.Name = "NewEmailBox" + this.panel1.Controls.Count;
NewEmailBox.Dock = DockStyle.Top;
this.panel1.Controls.Add(NewEmailBox);
}
private void button2_Click(object sender, EventArgs e)
{
foreach (Control item in this.panel1.Controls)
{
if (item is TextBox)
{
//Do your reading/validating here.
}
else
{
throw new InvalidCastException(string.Format("{0} was in Panel1 and is of type {1} not TextBox!", item.Name, item.GetType()));
}
}
}
Write a user control for each of the groupings you need. at least one One for address, one for email etc. then all of your validation, calls to your database access is contained in a single location
That is just good design. this way if you have multiple tabs for things like Home Information, Work Information, Emergency Contact Information, you can just place them on the form. This is pretty common for a user profile.
Then a listview for each grouping on a user profile page or whatever, that has edit/delete/add then popup a dialog with the appropriate user control in it.
Most simply, ListBox adove TextBox with Button.
Also you can use DataGridView, BuiltIn functionality for Add\Edit\Delete.
Here using DataGridView (ShowHeader set to false, EditMode to On Enter, with one Column with AutoSizeMode in Fill property)
The less of repeatable code you have, the better programmer you are.
Whenever you see a pattern (something what is repeatable), you could and you should try to optimize it. Unless it's something too small to worry.
In your case, determine first what is the basic of repeatable thing. Do you always have to enter address and email address? Then combine them into a control, which can carry out validation. Do you have to use this control often (or repeat N times)? Then maybe it make sense to switch to a list instead (ListBox, ListView or DataGridView).
Are you too lazy to bother configuring things? Then just optimize something what is obviously going to repeat: put validation into common method and call it from each TextBox event. Or make own TextBox with method build-in. Or do validation at once in the Ok button event by using loop.. or not by using loop.
To find best method you have to first decide best for who. Because customer want something shiny,easy to use, animated, with cats and boobs.. ok, without cats and boobs. The point is: how much work are you willing to put to have it best for the customer.
If I would have to enter table data (or data which form table), I'd go with DataGridView so it would looks like this.. or better:
I have a web form where I register a new employee. There're 3 parts in the form: Personal info, Address info, Special Status. But there's only one button for the whole form. When I submit the form all the information is updated to the database. So three Update statements are executed against the database. The methods are UpdatePersonalInfo, UpdateAddressInfo and UpdateSpStatus. Is there a way to check if there's been a change in any field in the certain part and run update method only if it's true. So something like this:
if (There's been any change to the personal data of the employee)
{
UpdatePersonalInfo;
}
if (There's been any change to the address information of the employee)
{
UpdateAddressInfo;
}
Sure I know, I can save all the previous values in a session object in PageLoad and then compare them one by one before running the method. But I thought maybe there's a magic way of doing this more easily.
Not sure that this is a better solution than any of the alternatives you already mentioned, but you could create a default handler to attach to the TextChanged, SelectedIndexChanged, etc events of your controls to keep track of which ones have changed.
List ChangedControls = new List(Of, String);
private void ChangedValue(object sender, System.EventArgs e) {
WebControl cntrl = (WebControl) sender;
ChangedControls.Add(cntrl.ID);
}
Then on your button click scour the ChangedControls list for the relevant controls.
I need to create a user control in C#.Net, which can be added to the application without being visible - just like the FolderBrowserDialog. It's a new window which I'll be using often so I think this is the right way. The window will be opened by envoking the showDialog-Method as known from the other dialog.
Any Idea?
Thanks and regards,
Daniel
Since all these "invisible" controls derive from Component class, you should start by reading the MSDN article on it: http://msdn.microsoft.com/en-us/library/system.componentmodel.component.aspx.
simply set Visible to false or isn't this what you're asking for ?
A UserControl is by definition not a Form; I think what you really want is a Component. That said, couldn't you really just create a new Form class that has the functionality you want? Whenever you want to display it, create a new instance and call ShowDialog. Or, if you want to preserve state, add an instance as a class member to your parent form, call its Show method whenever you want to display it, and add an event handler to its FormClosing event to check:
if (e.CloseReason == CloseReason.UserClosing)
and, if so,
e.Cancel = true;
Hide();
(This last part is to prevent errors if the user closes the form and then tries to display again after it's been disposed.)
I think more information may be needed, but if your crating a custom user control, the control should have a .Visible property. The follow is an example of how a button can be located on the form but hidden from a user.
button.Visible = true; // shows the button
button.Show(); // Shows the button
button.Visible = false; // hides the button
button.Hide(); // Hides the button
While the button may still be on the form/control, it will not be interactible by the user. You can still perform programmatic control on the button, but essentially it is not a user control while it is 'hidden'. If you want there to be a sort of hidden button that the user can click you will need to do other things to obtain this but It doesn't should like that is what you want.
This show/hide thought process sounds a lot like pains and confusion leftover from classic VB. The old form methods of show and hide, etc., were confusing and often left me as a developer in a position to not know whether an object existed or if was merely invisible. And checking was only trivial if you used On Error Goto to prevent a null reference. So right off I would advise not to think in terms of visibility unless you are doing something with a web page and need to maintain space and state.
First, create a Windows form and add it to your project, assuming that is the type of project that you are describing. Decorate the form with the proper controls, and where applicable, create properties to allow public access to the control values. Also set the DialogResult property of the buttons that either "OK" or "Cancel" the form. Give it an appropriate border style of either Fixed3D or FixedDialog. Maybe also set the property for where you want the form to appear on startup -- center parent, center screen, Windows default, etc. The event handlers for both "OK" and "Cancel" should invoke this.Close(); to close the window.
From the calling point in the code, here's some hypothetical code to get you going in the right direction. Write something like this in the place where you want to invoke your Dialog.
int intResult = 0;
string strResult = null;
MyDialogForm frm = new MyDialogForm();
frm.Title = "Select an Item";
frm.SomeProperty = 0;
frm.SomeOtherProperty = true;
if (frm.ShowDialog() == DialogResult.OK)
{
intResult = frm.Result;
strResult = frm.StringResult;
}
else if (frm.ShowDialog() == DialogResult.Cancel)
{
// User clicked the cancel button. Nothing to do except maybe display a message.
MessageBox.Show("Canceled Task");
}
...
// Somewhere further on down, but within scope, simply repeat
// what you just did, but without having to reinstantiate the
// form Window. But if you make it that far within the same
// scope, this method might be too busy and may need to be
// factored down.
So in short:
Scrap show/hide -- its not a good
practice.
Save the form data without
using an invisible form to save it;
that's the class's job.
If the UI requires a lot of flipping back and
forth between windows, check your
design for other alternatives for
solving the original problem. Maybe a design pattern such as MVC is for you, depending upon the size and complexity of your application.
Sound good?
You can put that control in a Panel. Set the panel height = 0 visible = false when you dont want to show the control.
And do the vice versa when you want to show it.
Derive from Control, not UserControl, and in the constructor set Visible = false.
Also create an event handler in the constructor.
VisibleChanged += new EventHandler(SetVisibleFalse);
Create a method named SetVisibleFalse.
private void SetVisibleFalse(object sender, EventArgs e)
{
if (Visible) Visible = false;
}