C# .NET

Naviagtion Buttons And C# .Net Image Lists

For the button images, we’ll have an ImageList that will allow us to select
a picture for all the buttons on the form.

We’ll add some navigation buttons, now. The buttons we’ll add will allow us
to go back one page, move forward one page, go to the home page, cancel the
page loading, and refresh the page. Instead of having text on our buttons, we’ll
have images.

For the button images, we’ll have an ImageList that will allow us to select
a picture for all the buttons on the form.

You’ll need some images for your buttons. We’re using a free icon set
we found online. There are plenty out there. Google is your friend,
here. Try the term “free icon sets” (with the quote marks).
Or search your hard drive for suitable images. You can search for files
that end in, say, GIF by entering *.gif in the Windows search box. Go
for an image size no bigger than 64 pixels high by 64 pixels wide. Image
types supported by the ImageList control are JPEG, GIF, BMP, PNG and
ICO.

So, add an ImageList control to your project (under the Components
category in the toolbox).

The ImageList has a ColorDepth property that we need to change. Our
images are in the PNG-24 format, where the 24 stands for the number of bits.
You’d think, then, that we’d need to set the ColorDepth to 24Bit. However, they
look awful at this Depth. When we switch to 32Bit, they look fine! But if your
images look awful, change the ColorDepth property.

The ColorDepth property of the ImageList control

To add images to your image list, click the Images button in the Properties
area, just to the left of Collection, in the image below:

The Images Collection of the ImageList control

When you click the small button, you’ll see a dialogue box appear. Click the
Add button to add some image to your ImageList. We’ve added five to ours, in
the image below:

The Images Colleciton Editor

(We’re using the light bulb as a refresh icon.) Click OK when you’re done.

Our images are 32 pixels high by 32 pixels wide. We can change to that size
in the ImageList properties area. The default is to have the images 16 by 16.
Type the new size into the ImageSize property, if you need to:

The ImageSize Collection of the ImageList control

Image Buttons on a C# Form

Adding graphics to your buttons is quite easy. Add a button to your form, using
the toolbox area on the left. Change the Name property to btnBack. Delete
the default text from the Text property of the button, leaving it blank. Resize
your button to a suitable size.

To add an image from your ImageList, locate the ImageList property for
btnBack. From the dropdown box, select the name of your ImageList:

The ImageList property of a button

Now locate the ImageIndex property. Click the dropdown box and you’ll
see a list of all your available images. Select the image you’re going to use
for your Back button. We’re using a left-pointing green arrow for ours, which
has the ImageIndex of 0:

Selecting an Image to go on a Windows Forms button

Once you’ve selected an image, take a look at your button. It should have your
picture on it:

An Image on a Windows Form button, C# 2012

The code for the back button is quite simple. So double click your button to
get at the coding window. Add the following:

if (webBrowser1.CanGoBack)
{

webBrowser1.GoBack();

}

We’re using an if statement first to check whether there is a page to go back
to. This is done with the CanGoBack property of the WebBrowser object.

If there is a page to go back to, we then use the built-in GoBack function.
This will force the browser to go back to the page you were previously looking
at.

Exercise
Add four more buttons to your Form. Set up the following properties for your
buttons:

Name: btnForward
Image: An image of your choice

Name: btnHome
Image: An image of your choice

Name: btnStop
Image: An image of your choice

Name: btnRefresh
Image: An image of your choice

When you’re done, your form may look something like ours:

Image Buttons on a C# Form

Test out your programme, though. Navigate to a web page like Google. Enter
something in the search page, just so as to bring up a second page. Now click
your Back button. You should be taken back to the previous page.

Exercise
Below, you’ll find four pieces of code. Add the right code to the appropriate
button:

if (webBrowser1.CanGoForward)
{

webBrowser1.GoForward();

}

webBrowser1.Stop( );

webBrowser1.GoHome( );

webBrowser1.Refresh( );

So you’re adding code to each of your remaining four buttons. When you’re done,
all four buttons should work, when you run your programme.

In the next lesson below, we’ll take a look at how to add Tool Tips.

|

Kaynak : https://www.homeandlearn.co.uk/csharp/csharp_s9p8.html ‘sitesinden alıntı

Yorum Yap