How does winform put the data of the two queries in the same dataGridView?

datatable operation.

The query is placed in dt1

Add dt1 of the query to dt2.

You can try to put the values of the two queries into the same list. Then bind that list to the DataGridView. Try to encapsulate the list you want to put depending on the situation.

You can put the values in the same data source, integrate them, and then bind them to the datagridview...

Wouldn't it be better to combine ,1] into the string allcells and then change the query statement?

string sql ="select distinct qpn,apn from where qpn in ",,allcells);

The allcell format should be "('a','b','c'That is, to combine everything into "('a','b','c'Strings in this format, so that a single query is done.

Add the queried data to the temporary table first. After all the data has been queried. Populate the data of the temporary table into the datagridview.

Update the data source of another DataGridView in the DataGridView event.

If there are 3 rows of data added to your datagridview1, will the corresponding query in datagridview2 also be 3 rows? If that's the case, you loop the number of rows in DataGridView1, put the queried data in a collection, and bind it to DataGridView2.

**You've written it out, and it's almost time to take out the datagridview1 row of data and assign a value.

DataGridView's DataSource property binds the return value of your SQL statement.

In fact, no matter how you design it, DataGridView is just a container for loading data. datagridview1 is equivalent to you query the information of all books, then select a book information, click the borrowing button, first judge the state of the book itself, if it is borrowed, it will give a prompt message, if it is not borrowed, use update to update the data status, and then query the borrowed data and display it in datagridview2. You can also consider the specific design in more detail: for example, when querying datagridview1, you can query according to the status, or you can only display unchecked books in datagridview, and datagridview2 can show borrowed books.

Then you can make a statistical query module.

It's actually quite simple.

All we need to do is drag and drop a DataGridView on the form, then double-click on the empty space of the form to add the parenthetical in the form1 load event of the file.

private void form1 load(object sender, eventargs e).