VB Multiple Judgment How to Use It helps me to add points

First, read the text file into the variables. Then use the instr function.

The problem description is not very clear, what are you adding, and where is it written? For example, writing to a database is different from writing to a text file, and there are big differences in the judgment conditions and writing methods.

If it is a database, you can check whether the same data exists first, and then do different processing according to the results.

If it's written to a file, it can be more complicated to determine.

Save an additional array after each write, and make a judgment to compare the contents of the array the next time you write. If you write to a text box, you can compare the contents of the text box directly, without the need for an additional array.

dim i as integer

for i = 0 to - 1

if "The name of your control" then 'me can be replaced with the form name of your control.

msgbox "exists"

eslemsgbox "does not exist"

end if

The name of the next control should be case-sensitive.

There is a way to try this, load a winsock control on error resume next

1234 'Test port 1234.

if err=0 then msgbox "Port 1234 is now available"

Hello, according to your description, or to judge whether the user has selected the list, this is completely achievable, and it is necessary to make a judgment when operating, and there will be an unexpected error when the user does not select the item. ** Below:

private sub command1_click()if < 0 then

msgbox "No items are selected"

elsemsgbox "The selected one is the first" & "Item:" &end if

end sub

private sub form_load()for i = 0 to 10

i & "1111111"

nextend sub

You can adjust the SelectedIndex property of the ListBox in the form's Form Load event.

To monitor whether a user has manipulated a listbox, you should start with the click and keypress events.

On the question of whether -1 is true or 1 is true, let me say a few words...

In fact, in VB6, as long as it is non-zero, it can be regarded as true, and zero is flase, but if you do the "non" operation, the main thing is to strictly equal true to -1, for example, we write a function:

function istrue() as boolean...end function

When we use this function, we need to perform a "non" operation on its return value, for example:

if not istrue then

If it returns false, execute it here.

.else if it returns true, execute it here.

.end if

In this case, only -1 and 0 can be non-arithmetic equal, and you can also try whether not -1 is =0 or not 0 is =-1

In general, you just need to think of non-zero as true.

No, what was said upstairs is not right.

There is no very precise definition in VB.

Generally true = -1

false = 0

But there are some controls inside.

true = 1

false = 0

It doesn't matter, just change it yourself.

dim b as boolean

b = return value.

This lets you know that it's true = -1

false = 0

But there are some controls that are true or false

1 is true and 0 is false It is recognized in the programming world whether you return an int (integer).

Upstairs is wrong, it's not the same as other languages in VB.

true=-1

false=0

If you don't believe me, you can try it yourself.

a=true

msgbox a+1

Let's see if it's =0

Add an option control, copy-paste, and create a control group.

For example, copy 6 ** as follows: private sub command1 click() for i = 0 to 5 if option1(i)value = true then msgbox option1(i).

caption & "Selected" nextend sub

Use too much. net, give me an idea, if it doesn't work, just go up. net bar.

First, get the handle of IE, then monitor the process of IE, and when the process of IE pops up, you can judge the information of the pop-up window.