Random image generation

Jim in Arizona

I was trying to create a random image generator. I'm using visual web dev
express with 2.0 framework.

On the web form page (mypage.aspx), I have an image control:

<asp:Image ID="Image1" runat="server" />

On the codebehind, (mypage.aspx.vb ), I have this code when a button is
clicked:

Dim imagegen() As String
Dim x As Short

x = CShort(Rnd() * 15)

imagegen(0) = "../images/ticketimages/atlascow.jpg"
imagegen(1) = "../images/ticketimages/carpool.bmp"
imagegen(2) = "../images/ticketimages/catsquirrel.jpg "
imagegen(3) = "../images/ticketimages/creature.jpeg"
imagegen(4) = "../images/ticketimages/fitnessescalato r.bmp"
imagegen(5) = "../images/ticketimages/frogcat.jpg"
imagegen(6) = "../images/ticketimages/helicopter.jpg"
imagegen(7) = "../images/ticketimages/highheelbike.bm p"
imagegen(8) = "../images/ticketimages/kisspandas.jpg"
imagegen(9) = "../images/ticketimages/libertylegs.jpg "
imagegen(10) = "../images/ticketimages/portapotty.bmp"
imagegen(11) = "../images/ticketimages/rabbitfingers.j pg"
imagegen(12) = "../images/ticketimages/santaplane.bmp"
imagegen(13) = "../images/ticketimages/sharkattack.jpg "
imagegen(14) = "../images/ticketimages/swissarmyant.jp g"
imagegen(15) = "../images/ticketimages/whaletail.jpg"

Image1.ImageUrl = imagegen(x)

When I tested the code, I got this error:

Server Error in '/' Application.
--------------------------------------------------------------------------------

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.NullRefe renceException: Object reference not set
to an instance of an object.

Source Error:
Line 346: Dim x As Short
Line 347: x = CShort(Rnd() * 15)
Line 348: imagegen(0) = "../images/ticketimages/atlascow.jpg"
Line 349: imagegen(1) = "../images/ticketimages/carpool.bmp"
Line 350: imagegen(2) = "../images/ticketimages/catsquirrel.jpg "
Source File: E:\hhsinternal\ Tickets\problem .aspx.vb Line: 348

Stack Trace:

[NullReferenceEx ception: Object reference not set to an instance of an
object.]
problem.btnRepo rtProblem_Click (Object sender, EventArgs e) in
E:\hhsinternal\ Tickets\problem .aspx.vb:348
System.Web.UI.W ebControls.Butt on.OnClick(Even tArgs e) +105
System.Web.UI.W ebControls.Butt on.RaisePostBac kEvent(String eventArgument)
+78
System.Web.UI.W ebControls.Butt on.System.Web.U I.IPostBackEven tHandler.RaiseP ostBackEvent(St ring
eventArgument) +7
System.Web.UI.P age.RaisePostBa ckEvent(IPostBa ckEventHandler
sourceControl, String eventArgument) +11
System.Web.UI.P age.RaisePostBa ckEvent(NameVal ueCollection postData) +33
System.Web.UI.P age.ProcessRequ estMain(Boolean
includeStagesBe foreAsyncPoint, Boolean includeStagesAf terAsyncPoint) +5670

--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:2.0.502 15.44; ASP.NET
Version:2.0.502 15.44
I'm a newbie with asp.net and vb.net. I've come a long ways but it seems
i've got a very long ways to go before I've got a clear understanding of
most of this stuff.

Thanks for the help!

Jim

Nov 23 '05 #1

Subscribe Reply

2881

Peter Rilling

You have not defined the size of the array, therefore imagegen(0) does not
exist.

"Jim in Arizona" <ti*******@hotm ail.com> wrote in message
news:uU******** ******@TK2MSFTN GP12.phx.gbl...

I was trying to create a random image generator. I'm using visual web dev
express with 2.0 framework.

On the web form page (mypage.aspx), I have an image control:

<asp:Image ID="Image1" runat="server" />

On the codebehind, (mypage.aspx.vb ), I have this code when a button is
clicked:

Dim imagegen() As String
Dim x As Short

x = CShort(Rnd() * 15)

imagegen(0) = "../images/ticketimages/atlascow.jpg"
imagegen(1) = "../images/ticketimages/carpool.bmp"
imagegen(2) = "../images/ticketimages/catsquirrel.jpg "
imagegen(3) = "../images/ticketimages/creature.jpeg"
imagegen(4) = "../images/ticketimages/fitnessescalato r.bmp"
imagegen(5) = "../images/ticketimages/frogcat.jpg"
imagegen(6) = "../images/ticketimages/helicopter.jpg"
imagegen(7) = "../images/ticketimages/highheelbike.bm p"
imagegen(8) = "../images/ticketimages/kisspandas.jpg"
imagegen(9) = "../images/ticketimages/libertylegs.jpg "
imagegen(10) = "../images/ticketimages/portapotty.bmp"
imagegen(11) = "../images/ticketimages/rabbitfingers.j pg"
imagegen(12) = "../images/ticketimages/santaplane.bmp"
imagegen(13) = "../images/ticketimages/sharkattack.jpg "
imagegen(14) = "../images/ticketimages/swissarmyant.jp g"
imagegen(15) = "../images/ticketimages/whaletail.jpg"

Image1.ImageUrl = imagegen(x)

When I tested the code, I got this error:

Server Error in '/' Application.
--------------------------------------------------------------------------------

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.NullRefe renceException: Object reference not set
to an instance of an object.

Source Error:
Line 346: Dim x As Short
Line 347: x = CShort(Rnd() * 15)
Line 348: imagegen(0) = "../images/ticketimages/atlascow.jpg"
Line 349: imagegen(1) = "../images/ticketimages/carpool.bmp"
Line 350: imagegen(2) = "../images/ticketimages/catsquirrel.jpg "
Source File: E:\hhsinternal\ Tickets\problem .aspx.vb Line: 348

Stack Trace:

[NullReferenceEx ception: Object reference not set to an instance of an
object.]
problem.btnRepo rtProblem_Click (Object sender, EventArgs e) in
E:\hhsinternal\ Tickets\problem .aspx.vb:348
System.Web.UI.W ebControls.Butt on.OnClick(Even tArgs e) +105
System.Web.UI.W ebControls.Butt on.RaisePostBac kEvent(String
eventArgument) +78

System.Web.UI.W ebControls.Butt on.System.Web.U I.IPostBackEven tHandler.RaiseP ostBackEvent(St ring
eventArgument) +7
System.Web.UI.P age.RaisePostBa ckEvent(IPostBa ckEventHandler
sourceControl, String eventArgument) +11
System.Web.UI.P age.RaisePostBa ckEvent(NameVal ueCollection postData) +33
System.Web.UI.P age.ProcessRequ estMain(Boolean
includeStagesBe foreAsyncPoint, Boolean includeStagesAf terAsyncPoint) +5670

--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:2.0.502 15.44;
ASP.NET Version:2.0.502 15.44
I'm a newbie with asp.net and vb.net. I've come a long ways but it seems
i've got a very long ways to go before I've got a clear understanding of
most of this stuff.

Thanks for the help!

Jim

Nov 23 '05 #2

Jim in Arizona

Yep. That was it exactly!

Thanks!

Jim

"Peter Rilling" <pe***@nospam.r illing.net> wrote in message
news:OQ******** ******@TK2MSFTN GP09.phx.gbl...

You have not defined the size of the array, therefore imagegen(0) does not
exist.

"Jim in Arizona" <ti*******@hotm ail.com> wrote in message
news:uU******** ******@TK2MSFTN GP12.phx.gbl...
I was trying to create a random image generator. I'm using visual web dev
express with 2.0 framework.

On the web form page (mypage.aspx), I have an image control:

<asp:Image ID="Image1" runat="server" />

On the codebehind, (mypage.aspx.vb ), I have this code when a button is
clicked:

Dim imagegen() As String
Dim x As Short

x = CShort(Rnd() * 15)

imagegen(0) = "../images/ticketimages/atlascow.jpg"
imagegen(1) = "../images/ticketimages/carpool.bmp"
imagegen(2) = "../images/ticketimages/catsquirrel.jpg "
imagegen(3) = "../images/ticketimages/creature.jpeg"
imagegen(4) = "../images/ticketimages/fitnessescalato r.bmp"
imagegen(5) = "../images/ticketimages/frogcat.jpg"
imagegen(6) = "../images/ticketimages/helicopter.jpg"
imagegen(7) = "../images/ticketimages/highheelbike.bm p"
imagegen(8) = "../images/ticketimages/kisspandas.jpg"
imagegen(9) = "../images/ticketimages/libertylegs.jpg "
imagegen(10) = "../images/ticketimages/portapotty.bmp"
imagegen(11) = "../images/ticketimages/rabbitfingers.j pg"
imagegen(12) = "../images/ticketimages/santaplane.bmp"
imagegen(13) = "../images/ticketimages/sharkattack.jpg "
imagegen(14) = "../images/ticketimages/swissarmyant.jp g"
imagegen(15) = "../images/ticketimages/whaletail.jpg"

Image1.ImageUrl = imagegen(x)

When I tested the code, I got this error:

Server Error in '/' Application.
--------------------------------------------------------------------------------

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.NullRefe renceException: Object reference not
set to an instance of an object.

Source Error:
Line 346: Dim x As Short
Line 347: x = CShort(Rnd() * 15)
Line 348: imagegen(0) = "../images/ticketimages/atlascow.jpg"
Line 349: imagegen(1) = "../images/ticketimages/carpool.bmp"
Line 350: imagegen(2) = "../images/ticketimages/catsquirrel.jpg "
Source File: E:\hhsinternal\ Tickets\problem .aspx.vb Line: 348

Stack Trace:

[NullReferenceEx ception: Object reference not set to an instance of an
object.]
problem.btnRepo rtProblem_Click (Object sender, EventArgs e) in
E:\hhsinternal\ Tickets\problem .aspx.vb:348
System.Web.UI.W ebControls.Butt on.OnClick(Even tArgs e) +105
System.Web.UI.W ebControls.Butt on.RaisePostBac kEvent(String
eventArgument) +78

System.Web.UI.W ebControls.Butt on.System.Web.U I.IPostBackEven tHandler.RaiseP ostBackEvent(St ring
eventArgument) +7
System.Web.UI.P age.RaisePostBa ckEvent(IPostBa ckEventHandler
sourceControl, String eventArgument) +11
System.Web.UI.P age.RaisePostBa ckEvent(NameVal ueCollection postData) +33
System.Web.UI.P age.ProcessRequ estMain(Boolean
includeStagesBe foreAsyncPoint, Boolean includeStagesAf terAsyncPoint)
+5670

--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:2.0.502 15.44;
ASP.NET Version:2.0.502 15.44
I'm a newbie with asp.net and vb.net. I've come a long ways but it seems
i've got a very long ways to go before I've got a clear understanding of
most of this stuff.

Thanks for the help!

Jim

Nov 23 '05 #3

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