How to use VB.NET expression
This article mainly introduces how to use VB.NET expression, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.
A VB.NET expression is a combination of one or more operations. The expression of VB.NET is not significantly different from that of other languages. Each expression that conforms to the VB.NET rules evaluates to a determined value. Operations on constants, variables, and calls to functions can all form the simplest expressions.
So far, we have learned the use of VB.NET expressions. Now, we use them in more complex structures.
In programming, conditional statements can determine the execution flow of the code according to the value of the VB.NET expression. In VB.NET, there are two kinds of conditional branching statements: If/Then/Else statements and Select/Case statements.
We can first analyze the specific concepts of VB.NET expressions from the following example.
The If/Then/Else statement is the most commonly used conditional statement. Its basic form is:
If condition Then statements1 [Else statements2]
It says: if condition is True, then execute statements1; otherwise execute statements2.
Example 2.4 (02-04.aspx) displays the greeting message according to the time.
< % If Hour(Now)< 12 Then Response.Write ("Good morning! Cindy!") If Hour(Now)=12 Then Response.Write ("Good noon! Cindy!") If (Hour(Now)>12 And Hour (Now)
< 18) Then Response.Write ("Good afternoon! Cindy!") If Hour(Now)>= 18 Then Response.Write
"Good evening! Cindy!")
% >
In the VB.NET expression example above, the function Hour () is the number of hours for the given date and time, and the Now function is used to return the current date and time. The program determines whether it is morning, noon or afternoon according to the time at that time, and gives the greeting information respectively. As we can see, this method is very simple, but in order to display a greeting message, the program has to take a value of Hour (Now) 4 times and perform 4 comparisons to complete, which is not good in terms of efficiency.
Thank you for reading this article carefully. I hope the article "how to use VB.NET expressions" shared by the editor will be helpful to everyone. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!
