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MessageBoxes - how to use them

MessageBoxes - how to use them, How to handle MessageBoxes and their results

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b.ihde

15 Dec, 2008 - 09:24 AM

Post #1

Welcome the this tutorial about MessageBoxes

In this tutorial i’ll show how to create a MessageBox with different buttons and icons.
At first let’s see what different kind of buttons exist:

OK
OK, Cancel
Yes, No
Yes, No, Cancel
Retry, Cancel
Abort, Retry, Ignore

And now what different kind of icons exist:
Attached Image

Error

Information
Attached Image

Question

Warning

A messagebox can be shown to show the user an information, or to let the user make a decision.

Per example: An easy information message would be “Text saved” with an Ok button.
A messagebox with a dicision to make would be “ Do you really want to quit?” with an Yes and No button.

Retrun the value of a messagebox:

If the user clicks a button, the program gets a DialogResult.

Here are the different return values and the buttons for the values:

OK --- DialogResult.OK
Yes --- DialogResult.Yes
No --- DialogResult.No
Abort --- DialogResult.Abort
Retry --- DialogResult.Retry
Cancel --- DialogResult.Cancel
Ignore --- DialogResult.Ignore

So let’s create some messageboxes:
( to show a messagebox use the Show() method )

We create a simple messagebox with a text, caption, Ok button and an information symbol:

At the beginning of every messagebox there is a event, in this case it is a button

Let’s create a button which should show a welcome massage.. double click on the button to insert a code.
There are 2 ways to write the code for a MessageBox:

1.

CODE

public void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("hello and welcome!", "welcome", MessageBoxButtons.OK, MessageBoxIcon.Information)
}

As we see the structure of this messagebox is the following:
MessageBox.Show("text", "caption", "buttons", "icon")

2.

CODE

public void button1_Click(object sender, EventArgs e)
{
string message = "hello and welcome"; // Message-Text
string caption = "welcome"; // TitleBar Text
MessageBoxButtons buttons = MessageBoxButtons.OK;
MessageBoxIcon icon = MessageBoxIcon.Information;

MessageBox.Show(message, caption, buttons, icon)
}

If we have more than one button we can set a defaultbutton.

In an example it would look like: (yes no - buttons)

CODE

public void button1_Click(object sender, EventArgs e)
{
string message = "Do you really want to quit?";
string caption = "exit";
MessageBoxButtons buttons = MessageBoxButtons.YesNo;
MessageBoxIcon icon = MessageBoxIcon.Question;
MessageBoxDefaultButton defaultbutton = MessageBoxDefaultButton.Button2;

MessageBox.Show(message, caption, buttons, icon, defaultbutton)
}

MessageBoxDefaultButton.Button1 (the first button) Yes is default
MessageBoxDefaultButton.Button2 (the second button) No is default

Now we look at how to handle a result:

So we create a messagebox with 2 buttons and the user has to decide what to do.
We create a quit-button:

CODE

public void button1_Click(object sender, EventArgs e)
   {
string message = "Do you really want to quit?";
string caption = "exit";
MessageBoxButtons buttons = MessageBoxButtons.YesNo;
MessageBoxIcon icon = MessageBoxIcon.Question;
MessageBoxDefaultButton defaultbutton = MessageBoxDefaultButton.Button2;
DialogResult result;

result = MessageBox.Show(message, caption, buttons, icon)

if (result == DialogResult.Yes)
   {
Close();
   }
}

If there is no definied event on a dialogresult, the messagebox will always close and nothing happens. So we don’t need to write an event for DialogResult.No in this example.

Now we can create a MessageBox with text, caption, buttons, icon and know how to get a result and how to handle the result.

At least we talk about the different overloaded Show methods

We already used 3 overloaded Show methods in this tutorial

Show(String)
in example:

CODE

public void button1_Click(object sender, EventArgs e)
{
string message = "Welcome";
MessageBox.Show(message);
}

Show(String, String)in example:

CODE

public void button1_Click(object sender, EventArgs e)
{
string message = "Hello and welcome!";
string caption = "Welcome";
MessageBox.Show(message, caption);
}

Show(String, String, MessageBoxButton)
in example:

CODE

public void button1_Click(object sender, EventArgs e)
{
string message = "Hello and welcome";
string caption = "Welcome";
MessageBoxButtons buttons = MessageBoxButtons.OKCancel;
MessageBox.Show(message, caption, buttons);
}

Show(String, String, MessageBoxButton, MessageBoxIcon)
This is the first example we used.

Show(string, string, MessageBoxButton, MessageBoxIcon, MessageBoxDefaultButton)
This is the second example we used.

Show(String, String, MessageBoxButton, MessageBoxIcon, MessageBoxDefaultButton , MessageBoxResult)
This is the third example we used.

Of course you don't have to use MessageBoxIcon and MessageBoxDefaultButton to use MessageBoxResult!
You can mix it a little bit, but for MessageBoxResult, of course, you need min. 2 buttons.

So, you are also able to code:
Show(String, String, MessageBoxButtons, MessageBoxResult)

CODE

public void button1_Click(object sender, EventArgs e)
   {
string message = "Message - Text"; // Message
string caption = "Title - Text"; // Caption
MessageBoxButtons buttons = MessageBoxButtons.YesNo;
MessageBoxDefaultButton defaultbutton = MessageBoxDefaultButton.Button2;
DialogResult result;

result = MessageBox.Show(message, caption, buttons)

if (result == DialogResult.Yes)
   {
// Event here
   }
}

Thank you very much for reading

Kindly regards

Benjamin Ihde