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error UserControl when run app????? (vs.NET2005)

I created a UserControl in Windows form. I built the control successfully. but when I added that control to an app then I got this error:

-----------
One or more errors encountered while loading the designer. The errors are listed below. Some errors can be fixed by rebuilding your project, while others may require code changes.

Object reference not set to an instance of an object.
Hide

at System.ComponentModel.ReflectPropertyDescriptor.SetValue(Object component, Object value)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeAssignStatement(IDesignerSerializationManager manager, CodeAssignStatement statement)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeStatement(IDesignerSerializationManager manager, CodeStatement statement)
--------------

I found that if without this code in usercontrol my app had no problem:

---------------
<Category("Get Data"), DefaultValue("")> Public Property GetTable() As String
Get
Return Me._tableName
End Get
Set(ByVal value As String)
Dim a As String = ""
For Each name As DataTable In Me._data.Tables
If name.TableName.ToUpper() = value.ToUpper() Then
Me._tableName = value
Exit Property
End If
Next
Throw New ArgumentException("there is no this table")
End Set
End Property
-----------------

thanks in advance

YoungBonzi

There's an area that you're not supposed to modify if you want to use the designer...it should be pre-commented.

If you undo what you changed in there, the designer should work again.

YoungBonzi

That area of code is from:
#pragma region Windows Form Designer generated code
...
to
...
#pragma endregion

If you could post the code you have in between there, perhaps we can see what the problem is. =)

YoungBonzi

I'm sorry I thought you were using C++...never mind what I wrote.

Daniel Van Der Werken

What happens if you don't use the attribute <Category("Get Data"), DefaultValue("")> ?

tatamaruri

ASKER

still error :(

tatamaruri

ASKER

Ah... I fixed it.
Because I had a condition "if" to get GetTable property. So when I had value in form but did not have in control class make it conflict.
Now I make some codes to remove that value in form and the error disappear.
Anyway... thanks all of you

tatamaruri

ASKER

I had another solution. I fix previous code to:

<Category("Get Data"), DefaultValue("")> Public Property GetTable() As String
Get
Return Me._tableName
End Get
Set(ByVal value As String)
If _data IsNot Nothing Then
For Each name As DataTable In Me._data.Tables
If name.TableName.ToUpper() = value.ToUpper() Then
Me._tableName = value
Exit Property
End If
Next
Throw New ArgumentException("there is no this table")
End If
End Set
End Property

sivachirravuri

I think the error was because the data list had nothing in it and the code was trying to use a value from it.

ASKER CERTIFIED SOLUTION

DarthMod

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