connecting access to C#

[mehdi4467]

Hi,
I am trying to connecting Access DataBase to C#,
my data base hase 3 table.
in c# when I configure data adapter and run

SELECT        account.*
FROM            account 

query, there is no problem and application run correctly. but when I trying to use 2 or 3 table from this data base

SELECT        account.ID, account.name, account.family, fish.bankname AS Expr2, fish.accountid, fish.fishid, bank.banknumber AS Expr3, 
                         bank.bankname AS Expr1, bank.bankid AS Expr4
FROM            ((account INNER JOIN
                         fish ON account.ID = fish.accountid) INNER JOIN
                         bank ON fish.bankname = bank.bankname) 

and when I finish this configuration and run the application and when run this line:

"oleDbDataAdapter1.InsertCommand.CommandText = "INSERT INTO account(name,family) VALUES ('" + nameTextBox.Text + "','" + familyTextBox.Text + "')"; "

I get below error:
"Object reference not set to an instance of an object.".

I attach my program.



thanks

[tlhintoq]

TIP: When you first created your question you were asked to wrap your code with [code] tags.

It really does help a bunch. Look how much easier it is to read now that someone has done it for you. Its the button with a '#' on it. More on tags. They're cool. Check'em out.

"How do I fix a 'object reference not set to an instance of an object' error?

The line your code stopped on while debugging holds all your answers.
One of the variables/objects was created but not initialized. For example:

string TempString;// Created but not initialized so this is still null
//versus
string TempString = string.empty;

Debug your project again. This time, when it breaks on a line look at the Locals pallet to see which variable/object is null. You can also hover your mouse over each variable and the hothelp will shows its value. One of them will be null.

[mehdi4467]

thanks
I see and I found a null object but I don't know what I do?
please see attache picture.

[tlhintoq]

I see and I found a null object but I don't know what I do?

Give it a value! Set it equal to something so it isn't null.

And then go to the bookstore and buy the Sam's "Learn C# in 21days" book and work through it from front to back, doing all the exercises.