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This article mainly introduces VB language if statement how to use, the text is very detailed, has a certain reference value, interested friends must read!

I. Review of relevant knowledge

Before we get started, let's review the format of the if statement.

Review the conditional statement knowledge points below:

Usage 1:

If condition then

Here is the code to execute under the conditions

end if

Usage 2:

If condition then

Here is the code to execute under the conditions

else

Code executed in case of non-compliance

end if

Second, if the statement is used in multiple conditions

Question: Can we use only one condition in an if statement?

Answer: You can use multiple conditions as conditions for an if statement

Question: How do you write conditions?

Consider the simplest if statement conditions:

if val(text1.text)>30 then

Here is the code to execute when the condition is met.

end if

val(text1.text) is a numeric value because val converts text to numeric value.

text1.text represents the text entered

If the text entered is 50, then text1.text has a value of 50, but this 50 is a text type (string type), and the string type is represented by "", which is actually "50".

Question: How do you write multiple conditions in an if statement?

We can use keywords and or.

The keyword and is used when multiple conditions are met at the same time before the conditions are finally considered met.

When the keyword or is used, as long as one condition is met, we will finally meet the final condition.

Examples:

Usage 1:

if condition 1 and condition 2 and condition 3 then

Here is the code that can only be executed if three conditions are met at the same time.

end if

Usage 2:

if condition 1 or condition 2 or condition 3 then

Here is the code that can be executed if there is only one condition.

end if

Usage 3 (mixing and and or):

if condition 1 and condition 2 or condition 3 then

Here, the results are matched in order from left to right. First, look at the result of combining condition 1 and condition 2, and then combine this result with condition 3 and then look at the result. The code that can be executed.

end if

Condition meets: i.e. the result value is true

Condition not met: i.e. result value is false

Some rules:

true and true Result is true

true and false Result is false

Conclusion: When using and, as long as one is false, the result is false

true or true Result is true

true or false Result is true

Conclusion: When using or, if either is true, the result is true.

III. About the acquisition of control text

So far, we have learned three controls. The acquisition of Chinese versions of these controls is listed as follows:

1. Example of obtaining text in label control label: label1.caption

2. Text box control textbox text acquisition example: text1.text

3. Example of button text acquisition: command1.caption

IV. Description of code comments

The symbol of comment code in VB uses single quotation mark under English state '

A comment is a description, explaining what the code means.

Annotated code is for illustration only and cannot be executed.

Code interpretation:

'Assign the text value of the button to the title of the form

Form1.Caption = Command1.Caption

V. Radio button controls

Radio button: control called optionbutton

If you double-click the radio button control on the interface, a click event is automatically generated.

The text modification attribute corresponding to the radio button is option.caption

VI. Control of Forms

Three ways to control windows

1. By default, you can omit the name of the form for controlling the properties of the form.

2. If the form under control is in this form, then you can use me instead of the form name

3. You want to control which form uses which form name directly

VII. Color control

How to use color:

1. Use system keywords, such as red, use vbred

2. Use the palette to find the desired color and copy the color code

3. Use the system function rgb to control

Three primary colors are red, green and blue.

Any color can be called from these three colors.

In rgb function, the value range of each color is 0~255, inclusive.

Red, green and blue correspond to the three parameters in the rgb function respectively, and the format is as follows:

rgb(red value, green value, yellow value)

Knowledge interface in this section:

This section of knowledge source code:

Private Sub Command1_Click()'Comment: Print the text content entered'Print Command1.Caption

Form1.Caption = Command1.CaptionOption1.Caption = "Red"Option2.Caption = "Black"Option3.Caption = "Yellow"End Sub

Private Sub Option1_Click()Form1.BackColor = RGB(0, 255, 255)

End Sub

Private Sub Option2_Click()Me.BackColor = vbBlackEnd Sub

Private Sub Option3_Click()BackColor = &HFFFF&End Sub

The above is "VB language if statement how to use" all the content of this article, thank you for reading! Hope to share the content to help everyone, more relevant knowledge, welcome to pay attention to the industry information channel!

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