Code for querying the DataGrid in winform

For the code of the DataGrid page in winform, We need to display data one by one when we use the DataGrid. When a button is clicked, the next record appears, that is, only one record is displayed at a time ,~ So I came up with the idea of using DataGrid paging. Of course, we also encountered a lot of problems in development, especially in details ~ Here, I would like to thank my friends reficul and Oscar for helping me a lot ~ ------------------------- Code example Public int nowpage = 1, pagecount = 1, pagesize = 1; // first define the variable and initialize private void button#click (Object sender, system. eventargs e) // Previous Page
{
Nowpage --;
Loaddata (sender, e );
} Private void button2_click (Object sender, system. eventargs e) // next page
{
Nowpage ++;
Loaddata (sender, e );
}
Private void loaddata (Object sender, system. eventargs E)
{
Try
{
String conn = "Server =.; user id = sa; Password =; database = northwind"; // connect to the database. In this case, the database is in SQL. // set the database connection.
Sqlconnection sconnstr = new sqlconnection (conn );
If (sconnstr. state. tostring () = "closed ")
{
Sconnstr. open ();
} Sqlcommand countcmd = new sqlcommand ("select count (*) as Co from employees", sconnstr); // read the total number of records
Sqldatareader countdr = countcmd. executereader (); If (countdr. Read ())
{
Pagecount = int32.parse (countdr ["CO"]. tostring ()/pagesize; // use the total number of records except the number of records displayed on each page = total number of pages
If (int32.parse (countdr ["CO"]. tostring () % pagesize> 0) // modulo operation,
{
Pagecount = pagecount + 1; // The number of pages displayed on more than one page is calculated by two pages.
}
If (pagecount <1) // if the number of less than one page is displayed, the value is calculated by one page.
{
Pagecount = 1;
}
}
Sconnstr. Close ();
Pageinfo. Text = "Total" + pagecount + "Page \ t No." + nowpage + "page ";
// Set database operation commands
If (nowpage> = pagecount) // if the current page value is greater than or equal to the total number of pages, the current page is the last page
{
Nowpage = pagecount;
}
If (nowpage <= 1) // if the current page value is less than or equal to one page, the current page is the first page
{
Nowpage = 1;
} Int start = (NowPage-1) * pagesize; // The start record of the current page is the last record of the total number of previous pages string command = "select * from employees "; // fill in the data and display it
Sqldataadapter SDA = new sqldataadapter (command, sconnstr );
Dataset DS = new dataset ();
SDA. Fill (DS, start, pagesize, "employees ");
Datagrid1.datasource = Ds. Tables ["employees"]. defaultview;
Datagrid1.setdatabinding (DS, "employees ");
}
Catch (exception ERR)
{
MessageBox. Show (ERR. Message. tostring ());
}
} Private void button3_click (Object sender, system. eventargs e) // homepage {
Nowpage = 1;
Loaddata (sender, e );
} Private void button4_click (Object sender, system. eventargs e) // the last page.
{
Nowpage = pagecount;
Loaddata (sender, e );
}