What does the phrase CheckBox cb CheckBox ct mean?

Implement a cast cast. Since the variable in the foreach loop uses control, the highest superclass of control, it cannot be directly assigned to the reference variable cb of the checkbox, so it must be transformed down to force the reference to the checkbox type.

Moreover, the function of the checkbox itself cannot be used in the control type reference, and must be transformed.

Also, provide a clear and simple way to do it.

foreach( control ct in with the as key word transformation, the advantage is that if the transformation is not successful, it will return a null value. Then use this to determine whether it is a checkbox or not

checkbox cb = ct as checkbox;

if( cb != null)

if(;

Walk through each control in .

Converts the controls traversed from form1 to the checkbox type.

Here you have to convert that every control is traversed from the form, and the default type is the control type, so.

It must be converted to the type you need to operate, and then operated.

Cast type conversion, cast ct to checkbox type and assign value to cb, but I don't think it's necessary to write like this here, ct is originally a checkbox type, so you can use it with or without casting.

for (int i = 0;i < i++) This is a traversal loop of the rows of the GridView.

In short, it is to click the button according to the checkbox status to delete it.

This is the operation of **content before the data is displayed**, which seems to be the only way to write, and it looks a bit disgusting.

Isn't this ** very difficult!!

The main thing is the use of database controls, in fact, you can understand it by reading the book slowly!!

I hope I can work hard to understand it, so that I can learn faster!!

Good luck.

Do I know if a radio selection is selected?

function checkradio()}

Try me this, it's okay.

above versions.

Is it that hard?

Why do you still use checkbox if you are single-selecting?

It's good to use radio......

Hello, ** as follows:

private void form1_load(object sender, eventargs e)

public void checkall(control c)else}}

Recursion is used so that checkboxes in other containers are also selected.

Remember to adopt yo ......

private void form1_load(object sender, eventargs e)

checkall(this);

public void checkall(control c)foreach (control ct incheckbox cb = ct as checkbox;

if (cb != null)

true;elsecheckall(ct);

Recursion is used so that checkboxes in other containers are also selected.

There are many items in the listview, and getview is the control that gets the item according to the item's position number.

convertview = , null);

This sentence is to use the itemrow below the layout as the style of each item in the listview. Here's how to assign a value to an item's control.

Here, let's mention the buffering mechanism of the listview, not only the listview, but also the gridview.

The landlord may not understand this viewholder.

Function: Suppose the entire listview has 1000 rows, you turn the page down, to the end, if you don't use the viewholder he will generate 1000 item instances, this will be oom in such a tight memory environment of Android, so, viewholder is to solve this. For example, if listview can only display 5 items per page, then you turn down the page and turn to the 6th entry, then the first entry is no longer in the display range, then the role of viewholder is to reuse the first article at the beginning, instead of incoming a control out, so that the second parameter of GetView is no longer null.

There should be a class in front of the viewholder, which puts a few controls in it, right?,if (convertview ==null)Start with this sentence It's very critical When you flip the following item, if it just appears, the following is not if the following statement is created If you have already flipped it, it won't be created This class has the effect of saving memory (if there are a lot of items, you have to create when you flip This class doesn't have to do this) This is a personal opinion.

This paragraph is the adapter of the custom listview, and the core is in the getview function, which is to draw each item in the listview, which can be customized.

HTML controls.

The same can be used in the background;

Use the HTML checkbox control, JS control to select all and not display, data-bound checkbox value with value, request["checkbox"] get.

You can use the server controls to solve the problem.

Then when the page is refreshed, you will find out if it has been selected.

Then you have to consider permissions, checkbox has a property enabled