Re: Asp.Net with C# - C# Discussion Boards

Re: I am trying to dispaly database values based on the combobox selection and i get this error "Data is null. this method cannot be called on null values"

5-Dec-13 21:17

Firstly, you should not use string concatenation in your query string. Read http://bobby-tables.com/about.html[^], and use proper parameterised queries. Secondly, you need to check the result of FileNameComboBox.Text, and indeed, the remainder of that statement to verify that you have actiually created a valid query.

Veni, vidi, abiit domum

WuRunZhe6-Dec-13 14:33

WuRunZhe

6-Dec-13 14:33

Well, which statement occur that error? If you don't know where it is, debug it and get exactly error statement.

And before rerun it, you have to check your sql express again. Smile | :)

Asp.Net with C#

ChandrakanthGaddam5-Dec-13 5:46

ChandrakanthGaddam

5-Dec-13 5:46

Hi
This is Chandrakanth.
My Query is, I have already Visual Studio 2010 professional in my system.Now i have installed Asp.net MVC4 in my Computer. That system is running with Microsoft XP Professional 2002 with Service Pack3. I was trying to open MVC4 application with Rajor engine from visual studio 2010 but it is giving error.

It says "Visaul Studio encountered problem and needs to close"

Can any one suggest me to work MVC4 Properly.

Thanks
Chandra

Chandrakanth

Simon_Whale5-Dec-13 6:06

Simon_Whale

5-Dec-13 6:06

Is anything showing up in your event logs?

Every day, thousands of innocent plants are killed by vegetarians.

Help end the violence EAT BACON

Eddy Vluggen5-Dec-13 8:00

Eddy Vluggen

5-Dec-13 8:00

ChandrakanthGaddam wrote:
I was trying to open MVC4 application with Rajor engine from visual studio 2010 but it is giving error.

Does it also happen if you create a new project from a blank template?

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

Abhinav S5-Dec-13 17:28

Abhinav S

5-Dec-13 17:28

Try a reinstall. It could help.

Apps - Color Analyzer | Arctic | XKCD | Sound Meter | Speed Dial

ChandrakanthGaddam6-Dec-13 3:38

ChandrakanthGaddam

6-Dec-13 3:38

Hi Thanks
for Your suggestion. I have re installed MVC4. It works now.

Thanks for your suggestions.

I am trying to update information using combobox to the database and the error it gives is "Object reference not set to an instance of an object"

thatraja6-Dec-13 2:20

thatraja

6-Dec-13 2:20

Check these
Visual Studio has encountered a problem and needs to close[^]
Solving the “Visual Studio needs to close” error[^]

thatraja

Code converters | Education Needed
No thanks, I am all stocked up. - Luc Pattyn
When you're wrestling a gorilla, you don't stop when you're tired, you stop when the gorilla is - Henry Minute

Member 103378795-Dec-13 2:46

Member 10337879

5-Dec-13 2:46

Below is my stored procedure

ALTER PROCEDURE [dbo].[sp_Workflow]
@TicketID int output,
@StaffID int output,
@Department nvarchar (50),
@FirstName nvarchar (50),
@TicketStatusID int output,
@TicketStatus nvarchar (50),
@TicketPriorityID int output,
@TicketPriority nvarchar (50)

AS
BEGIN

UPDATE dbo.Staff
SET
FirstName = @FirstName,

Department = @Department
WHERE StaffID= @StaffID

UPDATE dbo.TicketStatus
SET
TicketStatus = @TicketStatus
WHERE TicketStatusID =@TicketStatusID

UPDATE dbo.TicketPriority
SET
TicketPriority = @TicketPriority
WHERE TicketPriorityID =@TicketPriorityID

END

T Smile | :)

his is my code

private void Updatebutton_Click(object sender, EventArgs e)
{

con.Open();
SqlCommand cmd = con.CreateCommand();
cmd = new SqlCommand("sp_Workflow", con);
cmd.CommandType = CommandType.StoredProcedure;

cmd.Parameters.AddWithValue("@TicketID", System.Data.SqlDbType.Int).Value = TicketIDcomboBox.ToString();
cmd.Parameters.Add("@Department", System.Data.SqlDbType.NVarChar, 50).Value = MoveToDepartmentcomboBox.SelectedValue.ToString();
cmd.Parameters.Add("@FirstName", System.Data.SqlDbType.NVarChar, 50).Value = StaffcomboBox.SelectedValue.ToString();
cmd.Parameters.Add("@TicketStatus", System.Data.SqlDbType.NVarChar, 50).Value = ChangeTicketStatuscomboBox.SelectedValue.ToString();
cmd.Parameters.Add("@TicketPriorty", System.Data.SqlDbType.NVarChar, 50).Value = ChangeTicketPrioritycomboBox.SelectedValue.ToString();

MessageBox.Show("Are you sure you want to update?");

cmd.ExecuteNonQuery();
MessageBox.Show("Ticket Updated");
con.Close();
}

}

Re: I am trying to update information using combobox to the database and the error it gives is "Object reference not set to an instance of an object"

Pete O'Hanlon5-Dec-13 2:50

Pete O'Hanlon

5-Dec-13 2:50

The trick to solving an issue like this is to put a breakpoint in the start of your code and step through it, inspecting the values of various variables to see what they contain. For instance, looking at your code, it strikes me that the problem might possibly be with the line con.Open();. What if con is null? Where are you allocating it? BTW - you are showing a messagebox and then doing nothing with the result to prevent the query being executed. If I were you, I would move this to the top of the method and only proceed if the user clicks Yes.

Re: I am trying to update information using combobox to the database and the error it gives is "Object reference not set to an instance of an object"

BillWoodruff5-Dec-13 4:05

BillWoodruff

5-Dec-13 4:05

The first step is to figure out where the null reference error is happening.

Why not put a break-point at the entry to the Updatebutton_Click EventHandler code, and single-step through the code until you find the error.

If you call the 'ToString method on a ComboBox's SelectedValue when there is no value selected, you will get a null reference error: that's one of the possible sources of error to evaluate.

"What Turing gave us for the first time (and without Turing you just couldn't do any of this) is he gave us a way of thinking about and taking seriously and thinking in a disciplined way about phenomena that have, as I like to say, trillions of moving parts.

Until the late 20th century, nobody knew how to take seriously a machine with a trillion moving parts. It's just mind-boggling." Daniel C. Dennett

Re: I am trying to update information using combobox to the database and the error it gives is "Object reference not set to an instance of an object"

Abhinav S5-Dec-13 17:29

Abhinav S

5-Dec-13 17:29

Try debugging your code when this type of error occurs. This generally happens when you access a property or method of an object that itself is null.

Apps - Color Analyzer | Arctic | XKCD | Sound Meter | Speed Dial

check connection

Karim Hesham5-Dec-13 1:58

Karim Hesham

5-Dec-13 1:58

How can i detect an xbee if its connected to computer or not via USB ? and get notification if its connected or not

BillWoodruff5-Dec-13 2:19

BillWoodruff

5-Dec-13 2:19

I usually first listen to the sound of the computer and verify there is a humming.

Then I place a tea-spoonful of honey in an open dish near the computer and listen to see if there is a change in the pitch of the humming.

If that doesn't work, I use Google to locate two CodeProject articles in the top three search results returned by: [^], and start writing code while trying not to think of dead bees.

Smile | :)

good luck, Bill

Pete O'Hanlon5-Dec-13 2:47

Pete O'Hanlon

5-Dec-13 2:47

BillWoodruff wrote:
start writing code while trying not to think of dead bees

For the pure Monty Python that put in my mind, I award you the Order of Pete - it's a shiny badge of honour that you should wear with pride. To get your copy, simply print our your reputation page and look for the points that corresponds to the 5 and cut it out. Wear it with pride my friend.

OriginalGriff5-Dec-13 3:43

OriginalGriff

5-Dec-13 3:43

What is the sound of Half a Bee[^] buzzing?

File & folder overlay icon using C#

Wendelius5-Dec-13 2:21

Wendelius

5-Dec-13 2:21

Perhaps this article would help you: Detecting USB Drive Removal in a C# Program[^]

Tapas Saha4-Dec-13 22:03

Tapas Saha

4-Dec-13 22:03

Hello All,

On my project I want to change file and folder default icon same as dropbox. I have already made some Google and get a solution using vc++ but I don't have any experience on vc++ for that reason I am not able to apply this on my project.

So my request to you please suggest me, how can I do the same using C# ? I am familiar on C# language.

Please share with me me your valuable experience on this point. I am waiting for your valuable reply.

Thanks in advanced,
Tapas

Pete O'Hanlon4-Dec-13 22:17

Pete O'Hanlon

4-Dec-13 22:17

If you added C# to your Google search terms, or had done the search inside CP itself, you might have ended up here[^]. Make sure to read the comments as well.

Richard MacCutchan4-Dec-13 22:19

4-Dec-13 22:19

You beat me by seconds. Frown | :(

Veni, vidi, abiit domum

Richard MacCutchan4-Dec-13 22:18

4-Dec-13 22:18

There is a CodeProject article on the subject at Create Icons for Folders in Windows Explorer, Using C#[^].

Veni, vidi, abiit domum

Tapas Saha4-Dec-13 22:24

Tapas Saha

4-Dec-13 22:24

Thanks Richard for your valuable response.
I have already applied it and it working fine for folder icon change. But it not working for file icon change.

So please suggest me for file icon change.
Thanks once again,
Tapas

Richard MacCutchan4-Dec-13 23:10

4-Dec-13 23:10

Well a little bit of googling soon found http://social.msdn.microsoft.com/Forums/vstudio/en-US/c69713a1-7724-45f9-ab47-45fb85ef96fc/how-to-change-the-icons-of-file-and-folders-using-c-?forum=csharpgeneral[^].

Veni, vidi, abiit domum

Tapas Saha4-Dec-13 23:30

Tapas Saha

4-Dec-13 23:30

Thanks Richard once again,
Its not same that I am expecting. Actually I am trying to find a file icon overlay same as Dropbox/Tortorise SVN working folder.

Please give me some alternate solution.
Thanks,
Tapas

Richard MacCutchan4-Dec-13 23:34