I have a Winforms DataGridView in my application. When the user selects a row and hits enter, I load a new form with details related to that row. It takes about a second to get the data and show the screen. Some of the users are pretty fast and they start entering keystrokes relevant to the form e.g Pg Down/Pg Up, even before it loads and complain that the grid scrolls down instead of seeing the intended effect on the loaded Form.
I need a way to pause the keystroke messages from being processed until the form is loaded. Any ideas highly appreciated.
You could capture the WM_KEYDOWN message and ignore it if the form is loading (perhaps setting a flag) or you could post the messages to the currently loading form.
Have a look at IMessageFilter
Not a solution but a different approach:
what do you do now when the user selects a row and hit enter?:
Show form and load data
load data and show form
Option 1 is best combined with a loading icon/message. If you really have to enable the keystrokes then capture them and refire them when you are done loading. The new form will receive the keystrokes because it's topmost and active (if done correctly).
Can you not set the enabled property to false, and back to true once the data has loaded?
A simple bool check should do.
Create a bool, name it 'busy', and when the enter button is pressed check it to true.
if (!busy)
{
busy = true;
//do your thing
}
Simply check it back to false again when the loading is finished
Related
I am making a game, and to open up and close the store, you press S. While in the store, you have six different choices to buy from, but they are all buttons.
However, once you buy something, the focus is no longer on the form, but on the button, and the key down event is part of the form, therefore, because the focus gets switched from the form to the button, the key down event no longer works, and disables you from closing the store and continuing on with the game.
My question is how to set the focus back to a form once a button is press? I started out with visual basic, and the code would be something along the lines of form1.setfocus, but its totally different in c#.
I have tried Activating the form, .focus, a lot, and nothing seems to be setting the focus back to the form. Help would be greatly appreciated.
Form1.focus();
But I think, to get keyboard events on Form itself, you need KeyPreview set to true for the Form so that Form gets Keys first and then other controls.
Try:
form.Focus();
MSDN:
The Focus method returns true if the control successfully received input focus. The control can have the input focus while not displaying any visual cues of having the focus. This behavior is primarily observed by the nonselectable controls listed below, or any controls derived from them.
Tell me more
You can add the key down event to the buttons too.
I've got TextBoxes in a C# form. The user enters data, and then when they leave the control (almost always by hitting Tab), I check the data to make sure it's valid. If it is invalid, I want to highlight their text so they can immediately fix it rather than having to click it.
Right now, on Control.Leave, I validate their entry. This works just fine. However, since they hit Tab, right after they dismiss the error message, it goes on to the next object, even though I've got ((TextBox)sender).Focus();
How can I have the above line fire after the form Tabs to the next control.
You may want to look into Control.CausesValidation property
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.causesvalidation(v=vs.110).aspx
You can validate the control prior to the user leaving focus rather than waiting on Focus moving itself.
And here's MSDN documentation for Control.Validating event, does a good job at laying out the sequence of events when gaining / losing focus of a Control.
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.validating(v=vs.110).aspx
Notice how Control.Validating and Control.Validated are launched prior to Control.LostFocus. You can perform your validation step prior to allowing the user to lose focus of your Textbox.
There's also a pretty good previous answer on stackoverflow.com which outlines how to do this: C# Validating input for textbox on winforms
If you handle the Control.Validating event, setting e.Cancel to true will stop the change of focus from occurring.
Note that this method will also stop buttons from working, so you may need to set Control.CausesValidation to false on certain buttons.
You will also need the following snippet on the main form to allow the close button to work:
protected override void OnFormClosing(FormClosingEventArgs e) {
e.Cancel = false;
base.OnFormClosing(e);
}
Try using the LostFocus event on the TextBox to Focus it again
I have a C# .Net 3.5, winform (displaying graph) that needs to remain open as a front screen. I refresh the graph during the datagridview RowEnter event of the calling window. I open graph winform as show(), and use TopMost = true. Everything works fine till I open another application like Word; Graph window still remains in the front of Word.
Is there an application event gets triggered when another application opens on top of my application, when I can close the open graph screen. Or, please let me know if you have a suggestion about the different approach.
Look at Form.Deactivate Event. It is raised when the form loses focus and is no longer the active form. You can use this event to Close the form
Sorry but I can't get the sense of your question. You set TopMost=true and the next moment you want it to hide behind another application... ????
This solution method is 100% working, considering that the login form name is loginForm.
Simply create the following method:
private void hideLogin()
{
if (System.Windows.Forms.Application.OpenForms["loginForm"] != null)
{
System.Windows.Forms.Application.OpenForms["loginForm"].Hide();
}
}
Call this method through task:
Task HideLoginTask = new Task(hideLogin);
HideLoginTask.Start();
I have datagrid, when press update button I made popup window. I want to pause update process while user fills popup window.
You should start the Update only when you have all required info, not before the user fills in data in the popup window.
the first phase would be data capturing from user input, then you validate the data are correct, valid and sufficient and only then you start the update process whatever it means to you (you have given too few details...)
You can do it with Javascript. First you should capture the event and return false. This prevents a postback. When the dialog is completely filled out and closed you can send the information to the server via as ajax call or trigger a traditional post.
I would like to close a modal form when the user clicks outside (anywhere on the computer desktop) the modal form. How can we do this as a modal form is not meant to lose focus.
You need to hook mouse (and keyboard if required) and capture their events. Then check if the click happened outside the form (and area). If yes, flag a sign which can be read by the model form that it can close down.
Algo:
Hook mouse click event.
When callback function is called, check for the click position - if it's inside your form or not (you might need to translate the locations to Desktop locations - I hope you know how to!)
If the point is outside the form, set a flag (boolean or anything that makes you happy). Make sure the form can read the flag somehow.
Trigger an event for form to capture. In it's handler read the flag status. If true, close/unload the form.
This page will tell you technical details and functions.
I don't think you need to make it modal... then you can take siride's option of closing it on the Deactivate event.
The reason you don't need to make it modal: The first time you display it, it will have the focus and be topmost. Modal prevents you from clicking somewhere else, but you want to be able to click somewhere else... and when you do, the form goes away, so there are no modal needs.