Option Strict - Disallowed implicit conversion [Resolved]

[RobDog888]

I am using Option Explicit and Option Strict in my project and I have come accross an error where an implicit
conversion is taking place.

I have a LinearGradientMode and a String array. The LGM is being set from the srting array lie so. How do I convert
it so it wont error?

'drawParts() is the string array.
If Not IsNothing(drawParts(0)) Then _GradientPanel.DrawMode = [color=red]drawParts(0)[/color]

[kleinma]

drawParts(0) contains the actual constant name? like "horizontal" or whatever?

[ntg]

GradientPanel.DrawMode = CType(drawParts(0), System.Drawing.Drawing2D.LinearGradientMode)

[kleinma]

GradientPanel.DrawMode = CType(drawParts(0), System.Drawing.Drawing2D.LinearGradientMode)

will that work if the string contains the contant name and not the actual value of the enum?

[ntg]

Nope. Neither would GradientPanel.DrawMode = drawParts(0). You would need the value of the constant in the string, otherwise you'd need to fiddle with .ToString().

[RobDog888]

That should work, but I cant test it until I get all the conversion errors fixed.
This is the other one:

If Not IsNothing(drawParts(1)) Then _GradientPanel.PanelColor1 = CType(drawParts(1), System.Drawing.Color)

Says string can not be converted to a color.

[kleinma]

i was thinking you could do something like this.. not sure if its overkill.. im not even sure if it works since i dont have anything to test it against....

For Each EnumName As String In [Enum].GetNames(GetType(LinearGradientMode))
            If EnumName = drawParts(0) Then
                _GradientPanel.DrawMode = [Enum].GetValues(GetType(LinearGradientMode)).GetValue(0)
            End If
        Next

[ntg]

That shouldn't have something to do with Option Strict, right ? That's because System.Drawing.Color isn't an enumeration but a class with shared members. You shouldn't be able to do this using Option Explicit either.

I would think that should read:

If EnumName.ToString() = drawParts(0) Then

right ?

[kleinma]

well in my example enumname already is a string...

[Enum].GetNames(GetType(LinearGradientMode))

returns a string array

[ntg]

[RobDog888]

So then how do I fix the one for the color?

[kleinma]

color.fromname(drawParts(1))

i think should do it

[RobDog888]

Havent ran it yet but no error lines
Will this cover if the color is an RGB?

[kleinma]

Havent ran it yet but no error lines
Will this cover if the color is an RGB?

ummmmmmm NO, it takes a color name as a param..

there is color.FromArgb() which you can pass an integer color value, or pass a red, green, and blue value to (its overloaded).. so i guess it depends on how your string looks...

like if your string is "255,255,255" you might need to write a little function that parses and returns an array of integers to pass to the color.FromArgb() function

[RobDog888]

Damn, the thing is that its a property. So the user could enter a RGB or select a known color.

Got this error when I built the control:
Code generation for property 'Controls' failed. Error was: ''GraphicsModeConverter' is unable to convert 'MyUC.GradientPanelControl.GradientPanel' to 'System.ComponentModel.Design.Serialization.InstanceDescriptor'.'

[RobDog888]

Ok, I rebuilt both the control's project and the test project and the error went away. I tested under an known
named color and an RGB and it appears to work without errors but my properties are not expandable
properties.

Thanks for the help ntg and kleinma

Please see Expandable Properties thread for the other part of this issue.

[Aaron Young]

You can use the Parse method of the Enum type to convert a constant name into it's appropriate value, i.e.

_GradientPanel.DrawMode = [Enum].Parse(GetType(LinearGradientMode), drawParts(0))
 
If Not IsNumeric(drawParts(1)) Then
   _GradientPanel.PanelColor1 = [Enum].Parse(GetType(KnownColor), drawParts(1))
Else
   _GradientPanel.PanelColor1 = Color.FromArgb(Convert.ToInt32(drawParts(1)))
End If

[RobDog888]

Cool!

You always make things look so easy!