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This message was discovered on microsoft.public.dotnet.languages.csharp.
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jez123456 (VIP)

Hi, I have a vacation database with a calendar table to hold all the public
holidays and weekends.

I need a c# function which I pass in the vacation start and end dates and I
require it to return the duration. Here is my code but I canâ€™t see whatâ€™s
wrong.

public int Duration(DateTime Start, DateTime End)
{
string sqlCmd = "SELECT COUNT(dtmDate) FROM tblCalendar WHERE (blnWeekday =
1) AND (blnHoliday = 0) AND (dtmDate BETWEEN '" + Start.ToString("dd MMMM
yyyy") + "' AND '" + End.ToString("dd MMMM yyyy") + "')";
SqlCommand myCommand = new SqlCommand(sqlCmd,this.sqlConnection1);
this.sqlConnection1.Open();
int ans = (int) myCommand.ExecuteScalar();
this.sqlConnection1.Close();
}

How do I call this function to return the duration?
Is it something like:-

private void CalEnd_SelectionChanged(object sender, System.EventArgs e)
{
txtDuration =
Duration(DateTime.Parse(this.txtStart.Text),DateTime.Parse(this.txtEnd.Text));
}

Reply to this message...

Nicholas Paldino [.NET/C# MVP] (VIP)

jez,

It looks like your query is incorrect. Basically, you should be using
parameterized queries and passing the dates to your query through that.
Basically, it is something like this:

// Create the command text.
string sqlCmd = "select count(dtmDate) from tblCalendar where (blnWeekday =
1) and (blnHoliday = 0) and (dtmDate between @start and @end)";

// Create the command.
SqlCommand myCommand = new SqlCommand(sqlCmd, this.sqlConnection1);

// Set the parameters. Note that there are two operations being performed
here.
// The parameter is being added, and the value is being set on the return
value.
myCommand.Parameters.Add("@start", SqlDbType.DateTime).Value = start;
myCommand.Parameters.Add("@end", SqlDbType.DateTime).Value = end;

// Execute the command normally...

Hope this helps.

--
- Nicholas Paldino [.NET/C# MVP]
- Click here to reveal e-mail address

"jez123456" <Click here to reveal e-mail address> wrote in message
news:Click here to reveal e-mail address...
[Original message clipped]

Reply to this message...

Morten Wennevik

Hi jez123456,

Assuming your query returns the number of days (workdays?):

you need to return ans in your Duration method

public int Duration(DateTime Start, DateTime End)
{
string sqlCmd = "SELECT COUNT(dtmDate) FROM tblCalendar WHERE (blnWeekday =
1) AND (blnHoliday = 0) AND (dtmDate BETWEEN '" + Start.ToString("dd MMMM
yyyy") + "' AND '" + End.ToString("dd MMMM yyyy") + "')";
SqlCommand myCommand = new SqlCommand(sqlCmd,this.sqlConnection1);
this.sqlConnection1.Open();
int ans = (int) myCommand.ExecuteScalar();
this.sqlConnection1.Close();
return ans;
}

Assuming txtDuration is a TextBox, add ToString() to get the resulting number as a text string.

private void CalEnd_SelectionChanged(object sender, System.EventArgs e)
{
txtDuration.Text =
Duration(DateTime.Parse(this.txtStart.Text),DateTime.Parse(this.txtEnd.Text)).ToString();
}

If you only need Duration to get the string value of the result you can simplify it:

public string Duration(string startString, string endString)
{
    DateTime start = DateTime.Parse(startString);
    DateTime end = DateTime.Parse(endString);

    // query code

    return ans.ToString();
}

Then in the event do

txtDuration.Text = Duration(txtStart.Text, txtEnd.Text);

--
Happy Coding!
Morten Wennevik [C# MVP]

Reply to this message...

jez123456 (VIP)

Thanks Morten, that works ok when all code is in the same module behind a
webform, but I really need to be able store the Duration method in a separte
class and call it from the webform.

The line

txtDuration.Text =
> Duration(DateTime.Parse(this.txtStart.Text),DateTime.Parse(this.txtEnd.Text)).ToString();

gives the error: The name 'Duration' does not exist in the class or namespace

and the namespaces are the same.

Does the Duration method need to need to be delcared in the calling code?

"Morten Wennevik" wrote:

[Original message clipped]

Reply to this message...

Morten Wennevik

On Thu, 9 Sep 2004 02:55:04 -0700, jez123456 <Click here to reveal e-mail address> wrote:

[Original message clipped]

No, but the calling code needs to know where the Duration method is located.
If Duration is in another class, you need to use it on an object of that class.
Something like

MyDurationClass m = new MyDurationClass()
textBox1.Text = m.Duration(...);

Also, the Duration method might benefit from being static, in which case you would do

textBox1.Text = MyDurationClass.Duration(...)

--
Happy Coding!
Morten Wennevik [C# MVP]

Reply to this message...

	System.Data.SqlClient.SqlCommand
	System.Data.SqlDbType
	System.DateTime
	System.EventArgs
	System.Web.UI.MobileControls.TextBox
	System.Web.UI.WebControls.TextBox
	System.Windows.Forms.TextBox

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