Re: Error in retrieving data from SQL - C# Discussion Boards

21-May-09 15:48

Dear brothers,

I have read the book and searched from the internet. They told me the same way in retrieving data from SQL server. Unfortunately, it errors something when I do the same way. See my codes below :

private void btn_login_Click(object sender, EventArgs e)
{
string sSQL = "SELECT USERNAME, USERPASSWORD FROM TBL_USER WHERE USERNAME = '" + this.txt_username.Text + "' AND USERPASSWORD = '" + this.txt_username.Text + "'";
SqlCommand sCommand = new SqlCommand(sSQL, dbConnection.sqlCnn);

try
{
dbConnection.sqlCnn.Open();
SqlDataAdapter sReader = sCommand.ExecuteReader();
// It says : "Cannot implicitly convert type'System.Data.SqlClient.SqlDataReader' to 'System.Data.SqlClient.SqlDataAdapter'"

while (sReader.Read() == true)
{
frm_main frmparents = new frm_main();
frmparents.ShowDialog();
}
}
catch (Exception Er)
{
MessageBox.Show(Er.Message, "Exception");
}

Thanks for reading the entire article.

Chuon Visoth
Angkor Wat - Cambodia
asp.net - c sharp beginner

Luc Pattyn21-May-09 16:11

21-May-09 16:11

misCafe wrote:
AND USERPASSWORD = '" + this.txt_username.Text + "'";

BTW: normally one does not store the password, instead it gets hashed and it is the hash that gets stored and compared/searched.

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misCafe21-May-09 16:34

21-May-09 16:34

Oh yes, I have changed the text box. But it still errors when I press F5.
Then how?

Chuon Visoth
Angkor Wat - Cambodia
asp.net - c sharp beginner

Luc Pattyn21-May-09 17:00

21-May-09 17:00

Hi,

I have no experience with SqlDataAdapter, however the compiler is correct (obviously) when it says the result of ExecuteReader() is an SqlDataReader and not an SqlDataAdapter.

I suggest you look at the relevant documentation and/or google for correct examples.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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Show formatted code inside PRE tags, and give clear symptoms when describing a problem.

dan!sh 21-May-09 17:03

dan!sh

21-May-09 17:03

misCafe wrote:
SqlDataAdapter sReader = sCommand.ExecuteReader();

This is where the problem is. ExecuteReader method returns a DataReader object and NOT the DataAdapter object.

In case you need to use the DataAdapter, initialize it using the parameterized constructor and then use its Fill method. ObjectBrowser will help you finding about these.

जय हिंद

misCafe21-May-09 18:57

21-May-09 18:57

Many thanks for taking a part on this article Wink | ;)

Chuon Visoth
Angkor Wat - Cambodia
asp.net - c sharp beginner

MumbleB21-May-09 19:27

MumbleB

21-May-09 19:27

Also, please check Readup on SQL Injection.

Excellence is doing ordinary things extraordinarily well.

misCafe21-May-09 20:33

Repeated code with little difference

21-May-09 20:33

Oh well, It was my mistake. I may blind! It must be SqlDataReader in fact!

Thanks again!

Chuon Visoth
Angkor Wat - Cambodia
asp.net - c sharp beginner

Xenoserv21-May-09 12:09

Xenoserv

21-May-09 12:09

I'm wondering, how would I go about doing this in a much easier and logical manner? I have a lot of checkBox's being used and each one needs this exactly type of coding, just each one consecutively needs to have their object number +1 as shown below.

object cb1 = checkBox1.Tag;
object cb2 = checkBox2.Tag;
object cb3 = checkBox3.Tag;

if (checkBox2.Checked == true)
{
   cb2 = "1";
}
else
{
   cb2 = "0";
}

if (checkBox3.Checked == true)
{
   cb3 = "1";
}
else
{
   cb3 = "0";
}

if (checkBox1.Checked == true)
{
   cb1 = "1";
}
else
{
   cb1 = "0";
}

Help would be greatly appreciated!

Re: Repeated code with little difference

Luc Pattyn21-May-09 12:46

Re: Repeated code with little difference

21-May-09 12:46

Hi,

this does not make much sense to me. What is the use of storing the checked state in a string which is inside the Tag property, when the Checked state is already available as a boolean?

Anyway, this probably is what you asked for:

foreach(Control c in Controls) {
    CheckBox cb=c as CheckBox;
    if (cb!=null) cb.Tag=cb.Checked?"1":"0";
}

works whatever the number of checkboxes is, as long as they are all present in this.Controls
(if they are nested in panels, groupboxes, whatever, you may need some recursion).

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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Show formatted code inside PRE tags, and give clear symptoms when describing a problem.

_Maxxx_21-May-09 17:30

_Maxxx_

21-May-09 17:30

I suspect you are trying to be able to have a property with a 1 or 0 rather than a true or false (i.e. you dont ACTUALLY want to use Tag with a string, you are just using that as it is convenient)

If that's the case, why not make your own Checkbox:

using System.Windows.Forms;

namespace SomeNamespaceOrOther
{
	public class MyCheckBox : CheckBox
	{
		public int TrueFalseValue
		{
			get
			{
				return Checked ? 1 : 0;
			}
		}
	}
}

Then use it like your normalk checkbox, but access the TrueFalseValue property rather than the Tag or Checked property.

You can give it a 'setter' if you want - so setting the property to, say, 0 will make the checkbox unchecked.

___________________________________________
.\\axxx
(That's an 'M')

Sleek looking window application

humayunlalzad21-May-09 12:09

humayunlalzad

21-May-09 12:09

Can I use VStudio to design sleek looking windows applications, something like Google Chrome. If yes how?

Re: Sleek looking window application

EliottA21-May-09 12:37

EliottA

21-May-09 12:37

Yeah you can, UI's can be tricky to design, but there is no reason why not if you put in enough effort.

humayunlalzad wrote:
If yes how?

By coding.

Check out the CodeProject forum Guidelines[^]

Re: Sleek looking window application

_Maxxx_21-May-09 17:32

_Maxxx_

21-May-09 17:32

You might want to use WPF if you want 'prettyness'

___________________________________________
.\\axxx
(That's an 'M')

Re: Sleek looking window application

humayunlalzad22-May-09 5:21

humayunlalzad

22-May-09 5:21

Thanx I will try WPF

How to get custom attributes from a function called by delegate? [modified]

Anindya Chatterjee21-May-09 11:24

Anindya Chatterjee

21-May-09 11:24

suppose I have 3 functions.

1.
[CustomAttrib("First")]
public int Foo1(ref int x, out float y, SomeDelegate callback)

2.
[CustomAttrib("Second")]
public Stream Foo2(string name, SomeEnum enums);

3.
[CustomAttrib("Third')]
public void Foo3(string message, out double count, SomeStruct str);

Now what I want to do, is to validate each function according to their attribute. I want to create only one function named Validate which will validate all the above functions and then call them.

I tried to use delegate, lambda expression in Validate to pass the function, but nothing can get the attribute data.

I already tried :

public object Validate(Func<object> method) { .... } and call it as

Validate(() => Foo1(ref x, out y, DoCallBack));

or

public object Validate(Delegate method) { .... } & call it as

Validate(delegate() {return Foo2(null, SomeEnum.EnumValue); };

but none of them can get the attribute information of the called function
[Foo1, Foo2 etc.] in the body of Validate function.

Can anybody please suggest me any way-around to accomplish this task?

Anindya Chatterjee
--------------------------------------------------------
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2. But Watch ..

modified on Friday, May 22, 2009 12:32 AM

datagrid reorder

michaelgr121-May-09 10:19

michaelgr1

21-May-09 10:19

Hello,
I have datagrid in my application.
I want to create event that will be raised when datagrid columns were reordered by user (and then do something).
how can i do it?

Re: datagrid reorder

Luc Pattyn21-May-09 10:30