[RESOLVED] convert string to color

[dreamdelerium]

hey everyone, just need some help converting a string to color. i use the colordialog to the user can pick a color, which is then saved into a db. when i load the color to fill a lable it comes as a string. so, how do i convert:

Color [A=255, R=128, G=128, B=255] to color

also, when i use the colordialog, it will save basic colors as color[TheColor] and complex as the one above. to be uniform, is there a way to have the colordialog always return a hex value? or do i need to write a function for that?

thanks
jason

[Pradeep1210]

Use the FromName, FromArgb or FromKnownColor method of the Color class.

Dim c As Color
 
'if you know the common name
c = Color.FromName("red")
 
'if you know the color numeric values
c = Color.FromArgb(255, 255, 255)       'red, green, blue: see other overloads too for more options 
 
'if you know the knowncolor name
c = Color.FromKnownColor(KnownColor.Red)

Also have a look at ToArgb, ToKnownColor, ToString methods for inverse of this.


Pradeep

[Atheist]

I'd advice you to use the System.Drawing.ColorTranslator.ToHtml method on the color to get a string with the HTML string representation of it, and save that to the database instead.
When you get the string from the database later, use the System.Drawing.ColorTranslator.FromHtml to make it into a Color again

[jmcilhinney]

I'd advice you to use the System.Drawing.ColorTranslator.ToHtml method on the color to get a string with the HTML string representation of it, and save that to the database instead.
When you get the string from the database later, use the System.Drawing.ColorTranslator.FromHtml to make it into a Color again

I'd be more inclined to save an Integer to the database and use Color.ToArgb and Color.FromArgb unless there's a reason to go into the database and edit the values, which would be easier with the string.

[Deepak Sakpal]

Better you store the 32-bit ARGB value. It's basically a numeric value. If you code this way then there won't be any need to write a function to extract the color value. Here is some piece of code:

Public Class Form1
 
    Private Sub Button1_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs _
    ) Handles Button1.Click
 
        Dim clrDialog As New ColorDialog
        If clrDialog.ShowDialog = Windows.Forms.DialogResult.OK Then
            TextBox1.Text = clrDialog.Color.ToArgb.ToString ' Store this value in DB.
        End If
        clrDialog.Dispose()
    End Sub
 
    Private Sub Button2_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs _
    ) Handles Button2.Click
 
        ' Get the ARGB value from DB and use it.
        TextBox1.BackColor = Color.FromArgb(CInt(TextBox1.Text))
    End Sub
 
End Class

EDIT: Damn.... When I started reply, there were no replies and now three replies already posted. Am I that much slow

[dreamdelerium]

thanks everyone.

[skywola]

Here is some things I refactored today, it may have errors, but as far as I can tell, nothing horrible.
I use these a lot in the application I wrote that colors text. Generics make life so easy!

This may have some interwoven-ness with the app I built using it, i.e., you will see one instance
were I refer to FrmMain, so beware, these are not necessarily made to work alone, but it would
be REAL easy to make them that way. . .

    Public Function getColorComponentsRGBValuesFromColor(ByVal clr As Color) As Stack(Of Byte)
        Dim R, G, B, A As Byte
        Dim colorStringStack As New Stack(Of String)
        Dim colorByteStack As New Stack(Of Byte)

        Try
            colorStringStack = getColorARGBValuesFromString(clr.ToString)
            If colorStringStack.Count > 0 Then
                A = CByte(colorStringStack.Pop) ' 255 if not transparent
                R = CByte(colorStringStack.Pop)
                G = CByte(colorStringStack.Pop)
                B = CByte(colorStringStack.Pop)
            Else   ' not a custom color, get color from name
                R = clr.R
                G = clr.G
                B = clr.B
                A = 255  ' defaulting to non-transparent
            End If
            colorByteStack.Push(B)
            colorByteStack.Push(G)
            colorByteStack.Push(R)
            colorByteStack.Push(A)

        Catch ex As Exception
            genFns.reportError("Error:" & ex.StackTrace & ". . . ." & vbCrLf & Err.Description, ex)
        End Try
        Return colorByteStack
    End Function

    ' used 3 times
    Public Function getColorARGBValuesFromString(ByVal ARGBStr As String) As Stack(Of String)
        Dim Astr As String = ""
        Dim Rstr As String = ""
        Dim Gstr As String = ""
        Dim Bstr As String = ""
        Dim colorList As New List(Of String)
        Dim colorStack As New Stack(Of String)
        Try
            ' check for a custom color i.e. A=255, R= 0, G=255, B=64
            ' This function first checks for a custom color, it one is present it returns TRUE
            ' then it fills the array with the color numbers for A, R, G, B
            'storedColor = "A=255, R=0, G=255, B=164"  ' for info and testing
            colorList.AddRange(Strings.Split(ARGBStr, ","))
            For Each item In colorList
                colorStack.Push(item)
            Next
            ' colorStack holds {"B=64", "G=255", "R=0", "A=255"} is it is a custom color
            ' If it is a custom color, convert to get a color
            If colorStack.Count = 4 Then
                Bstr = Strings.Replace(colorStack.Pop, "B=", "")
                Gstr = Strings.Replace(colorStack.Pop, "G=", "")
                Rstr = Strings.Replace(colorStack.Pop, "R=", "")
                Astr = Strings.Replace(colorStack.Pop, "A=", "")
                colorStack.Clear()
                colorStack.Push(Bstr)
                colorStack.Push(Gstr)
                colorStack.Push(Rstr)
                colorStack.Push(Astr)
                Return colorStack
                Exit Function
            End If

        Catch ex As Exception
            genFns.reportError("Error:" & ex.StackTrace & ". . . ." & vbCrLf & Err.Description, ex)
        End Try
        Return colorStack
    End Function

    ' get the color value of this string 
    Public Function interpretColorString(ByVal colorString As String, Optional ByVal z As Integer = -1) As Color
        Try
            Dim colorVal As Color
            Dim colorStack As New Stack(Of String)

            If InStr(colorString, "Color [") > 0 Then
                colorString = Strings.Replace(colorString, "Color [", "")
                colorString = Strings.Replace(colorString, "]", "")
            End If

            ' check for a custom color i.e. A=255, R= 0, G=255, B=64
            ' This function first checks for a custom color, it one is present it returns 
            ' a Stack(Of String) with the color numbers for A, R, G, B

            colorStack = getColorARGBValuesFromString(colorString)
            If colorStack.Count > 3 Then
                Dim A, R, G, B As String
                Dim Aint, Rint, Gint, Bint As Integer
                A = colorStack.Pop
                R = colorStack.Pop
                G = colorStack.Pop
                B = colorStack.Pop
                Aint = CInt(A)
                Rint = CInt(R)
                Gint = CInt(G)
                Bint = CInt(B)
                colorVal = Color.FromArgb(Aint, Rint, Gint, Bint)
            Else
                If colorString = "" And z > -1 Then
                    colorVal = FrmColor.colorArray(z)
                Else
                    colorVal = Color.FromName(colorString)
                End If
            End If
            Return colorVal

        Catch ex As Exception
            genFns.reportError("Error:" & ex.StackTrace & ". . . ." & vbCrLf & Err.Description, ex)
        End Try
    End Function