Re the last id value - C# Discussion Boards

14-Jun-06 21:22

Hi there,

A little quistion.

I have a Form that contain's a textfield and a Button.
If the button is pressed a new form opens (the old form stays open too)

The new form contains a datagrid where the user can select a customer.

On the dubble click of the row the form closes and should put this value into the textfield.

the select row is not the problem.
the dubbelclick isn't a problem as wel.

the problem is how can i fill the textbox when dubbelclicked on the row.

I can pass the data between the forms. and usaly i use the initialize component or formload to fill up the forms.
But in this case he doesn't reopen the first form.

albCode14-Jun-06 22:07

albCode

14-Jun-06 22:07

on double click event :

Form1 frm1 = new Form1();<br />
frm1.TextBox1.Text =

selectedrow text

Rmokkenstorm14-Jun-06 23:47

14-Jun-06 23:47

that opens a new form and that is not exactly what i want cause he loads my populate textbox event which is defined by initialzi components.

albCode14-Jun-06 23:57

albCode

14-Jun-06 23:57

Form1 frm1 = new Form1();<br />
frm1.TextBox1.Text =

//value

this code doesn't open form as u see it's declared new instance of Form and then via that instance it's refered to text of textbox.

Rmokkenstorm15-Jun-06 0:31

15-Jun-06 0:31

oke open was maybe a bad word to use..
but if i use this he will go to the initialize components section of the form and i wan't to skip that part i really don't want him to do this..
cause there he loads an event wich contains data from a previous form. any way he doesn;t load this 2 times.

Rmokkenstorm15-Jun-06 0:39

15-Jun-06 0:39

If i want to bypass this with a if else sting.empty he says that he cannot covert string to bool.

Re the last id value

Tamimi - Code14-Jun-06 20:15

Tamimi - Code

14-Jun-06 20:15

i used to get the last value (in order to insert new record) like this
(select max(IdColumnName) from TableName) , but it seems its not the best
approach to do this , why??
why (select @@identity) is consider as the good way ??

thank you all

Tamimi - Code

Guffa14-Jun-06 20:47

Guffa

14-Jun-06 20:47

Getting the largest id is not a safe way to get the id of the record. If another user added a record at the same time, you will get the wrong id. Consider this scenario:

:: User 1 adds a record, which gets id 42.
:: User 2 adds a record, which gets id 43.
:: User 1 gets the highest id, which is 43.
:: User 2 gets the highest id, which is 43.

Now both users think that they added the record with id 43.

Using @@identity on the other hand is completely safe. A user will always get the last id that was created in the database session, e.g. with the same database connection.

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Tamimi - Code14-Jun-06 21:03

Tamimi - Code

14-Jun-06 21:03

you know.. the best way to undersatand this is to try it;)

i will try to check it on a small application

thanks

Tamimi - Code

J4amieC14-Jun-06 22:07

J4amieC

14-Jun-06 22:07

Guffa wrote:
Using @@identity on the other hand is completely safe

In SQL Server, you never used to be assured to 100% always get the right id with @@identity. So in sql server 2000 they added a built in fuction called SCOPE_IDENTITY() which is AFAIK 100% guaranteed to get you the right ID.

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Guffa15-Jun-06 1:12

Guffa

15-Jun-06 1:12

Correct. I mentioned the scope_identity function in the previous thread:
http://www.codeproject.com/script/comments/forums.asp?forumid=1649&mode=all&userid=3050175&select=1532206&df=100&tid=1531522#xx1532206xx

AFAIK there is only a difference between @@identity and scope_identity() when you are using triggers that uses inserts.

@@identity will always return the last id created in the session, but if the trigger also inserts a record you will get the id of that record instead of the id from the insert that caused the trigger to run.

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ScreenSaver

picasso214-Jun-06 19:35

picasso2

14-Jun-06 19:35

I created a screensaver project, used all the default settings. When the project is completed, it works fine with two images (SSaverBrackground,SSaverBrackground2). I cannot find A way to add more images.

Any help is greatly appreciated

Using VS 2005

databindings...combobox

rzvme14-Jun-06 19:19

rzvme

14-Jun-06 19:19

i have a dataset that is filled from a webservice. The dataset will contain a table with 2 columns. What's the code to bind the DysplayMember property to one of the Columns and the Value member to the other one??

rzvme

rah_sin14-Jun-06 19:25

rah_sin

14-Jun-06 19:25

u can use

comboBox1.DataSource=Dset.Tables["table name"];
comboBox1.DisplayMember="column1 name";
comboBox1.ValueMember="column2 name";

rahul

rzvme14-Jun-06 19:57

rzvme

14-Jun-06 19:57

tried that too: error:An unhandled exception of type 'System.ArgumentException' occurred in system.windows.forms.dll

Additional information: Could not bind to the new display member.

rzvme

rah_sin14-Jun-06 20:08

rah_sin

14-Jun-06 20:08

try to check that u have used same column names which are used in table in database.

rahul