I want to setup property value in property page but there "Object reference not set to an instance of an object."

What is it?

And how i can debug my controls?
0
Yola00
9/25/2003 8:30:04 AM
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Hi,

we would pretty much more information. What kind of is the property in question? Is it string, URL or what?
You would be able to debug controls by having controls on separate Web Control Library project and then the actual consuming app on project that uses these controls (references the Web Control Library project). Put breakpoints on the code for your controls and run F5 in Visual Studio to start debugging (like you nornmally would). That's it.
Thanks,

Teemu Keiski
Finland, EU
0
joteke
9/25/2003 6:48:58 PM
If you access childobjects of your custom control in the public properties of your control;

And use these properties on your aspx page in the for example On_Page Load event, these child objects are NOT created yet. This because the CreateChildControls functions has not fired yet.
So use the property to set an internall value variable and use that in the CreateChildControls function (of your custom control) to populate the child control you tried to access via the property.
This is what i found out so far, but currently still working on how to get better custom controls.
0
henkm
9/26/2003 7:48:03 AM
Yeah,

on initial request CreateChildControls is called at PreRender but on postback they are created when postback data processing has started/starting.
One can make sure Controls are created at certain time by calling EnsureChildControls. So if it is a question of property of child control, always call EnsureChildControls before trying to access the property. This way one makes sure child controls exist.
Thanks,

Teemu Keiski
Finland, EU
0
joteke
9/26/2003 7:54:16 AM
I create Solution with two projects first - class library with my control, second - web app which use control. When i set breakpoint in my control project and try to run main app (startup project) it says "The project with the output type of Class Library cannot be started directly". Whay must i do?
0
Yola00
9/26/2003 12:26:58 PM
You just have wrong project as startup project (it is the first project created in solution typically). Right-click the actual web project name and pick from menu "Set as Startup Project"
Thanks,

Teemu Keiski
Finland, EU
0
joteke
9/26/2003 12:31:22 PM
I was wrong. I made web app as startup project and it starts.

But i don't now how to debug it. May be somebody give me links to article about it?
But remember? in design time my object generate error too, property of type String.
0
Yola00
9/26/2003 12:34:06 PM
"Object reference not set to an instance of an object." - in Text property of my control.

At my control i was create two properties ErrorMessage and Text. After chnage property name from Text to Text1 it start working! But! In properties list property with name Text1 didn't appear and property Text didn't remove and same mistake in that property. So i can create only limited properties set? Can anybody help? Send me test component? simple. Or better if discribe me my error!
0
Yola00
9/29/2003 12:08:27 PM
Show some code....
Thanks,

Teemu Keiski
Finland, EU
0
joteke
9/29/2003 12:59:28 PM
Finally it start working.

But some problem still there.
How i can use DefaultValueAttribute. It's not working. No value in property field appear efter i drop component on the form.
When i do some changes in my control i must remove - add reference in my project and remove - add control on my form, may be exist another method?
And for that property:
[Bindable(false),
Category("Validator")]
public System.Drawing.Color ValidatorColor
{
get
{
try
{
return (System.Drawing.Color)ViewState["validatorColor"];
}
catch (NullReferenceException e)
{
return System.Drawing.Color.Red;
}
}
set { ViewState["validatorColor"]= value; }
}
in property field in designer it writes: "Object reference not set to an instance of an object."
0
Yola00
10/2/2003 8:21:05 AM
Reply:

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