VB.Net 比较运算符
VB.Net 运算符下表显示了VB.Net支持的所有比较运算符。 假设变量A保持10，变量B保持20，则：
| 运算符 | 描述 | 示例 |
|---|---|---|
| = | Checks if the values of two operands are equal or not; if yes, then condition becomes true. 检查两个操作数的值是否相等; 如果是，则条件变为真。 |
(A = B) is not true. |
| <> | Checks if the values of two operands are equal or not; if values are not equal, then condition becomes true. 检查两个操作数的值是否相等; 如果值不相等，则条件为真。 |
(A <> B) is true. |
| > | Checks if the value of left operand is greater than the value of right operand; if yes, then condition becomes true. 检查左操作数的值是否大于右操作数的值; 如果是，则条件变为真。 |
(A > B) is not true. |
| < | Checks if the value of left operand is less than the value of right operand; if yes, then condition becomes true. 检查左操作数的值是否小于右操作数的值; 如果是，则条件变为真。 |
(A < B) is true. |
| >= | Checks if the value of left operand is greater than or equal to the value of right operand; if yes, then condition becomes true. 检查左操作数的值是否大于或等于右操作数的值; 如果是，则条件变为真。 |
(A >= B) is not true. |
| <= | Checks if the value of left operand is less than or equal to the value of right operand; if yes, then condition becomes true. 检查左操作数的值是否小于或等于右操作数的值; 如果是，则条件变为真。 |
(A <= B) is true. |
尝试以下示例来了解VB.Net中提供的所有关系运算符：
Module operators
Sub Main()
Dim a As Integer = 21
Dim b As Integer = 10
If (a = b) Then
Console.WriteLine("Line 1 - a is equal to b")
Else
Console.WriteLine("Line 1 - a is not equal to b")
End If
If (a < b) Then
Console.WriteLine("Line 2 - a is less than b")
Else
Console.WriteLine("Line 2 - a is not less than b")
End If
If (a > b) Then
Console.WriteLine("Line 3 - a is greater than b")
Else
Console.WriteLine("Line 3 - a is not greater than b")
End If
' Lets change value of a and b
a = 5
b = 20
If (a <= b) Then
Console.WriteLine("Line 4 - a is either less than or equal to b")
End If
If (b >= a) Then
Console.WriteLine("Line 5 - b is either greater than or equal to b")
End If
Console.ReadLine()
End Sub
End Module
当上述代码被编译和执行时，它产生以下结果：
Line 1 - a is not equal to b
Line 2 - a is not less than b
Line 3 - a is greater than b
Line 4 - a is either less than or equal to b
Line 5 - b is either greater than or equal to b
除了上述，VB.Net提供了三个比较运算符，我们将在以后的章节中使用; 不过，我们在这里给出一个简短的描述。
1、Is 运算符 -它比较两个对象引用变量，并确定两个对象引用是否引用相同的对象，而不执行值比较。 如果object1和object2都引用完全相同的对象实例，则result为True; 否则，result为False。
2、IsNott 运算符 - 它还比较两个对象引用变量，并确定两个对象引用是否引用不同的对象。 如果object1和object2都引用完全相同的对象实例，则result为False; 否则，result为True。
3、Like 运算符 - 它将字符串与模式进行比较。
