I have third party object which contain so many member with integer, string and Boolean. I want to update that record whose value is not null or blank
You can use reflection to achieve what you want:
Sub Main()
Dim obj As Test = new Test()
Dim type As Type = GetType(Test)
Dim info As PropertyInfo() = type.GetProperties()
For Each propertyInfo As PropertyInfo In info
Dim value As String = propertyInfo.GetValue(obj)
If propertyInfo.PropertyType = GetType(String) And String.IsNullOrEmpty(value)
' empty value for this string property
End If
Next
End Sub
public Class Test
Public Property Test As String
End Class
Related
I've two structures and one class in my namespace Dimension. These structures are Dimension.Derived and Dimension.Basis. The class was called Exponent. I had overrided the Function ToString() of my class to get the DisplayNameAttribute of properties in my structure Dimension.Derived.
Public Overrides Function ToString() As String
Dim oType As Type
oType = GetType(Dimension.Derived)
Dim colMemberInfo() As PropertyInfo = oType.GetProperties
For Each oMemberInfo In colMemberInfo
If Me = oMemberInfo.GetValue(oMemberInfo) Then
Dim de As New Dimension.Exponent
de = oMemberInfo.GetValue(oType)
Dim attr() As DisplayNameAttribute = DirectCast(oMemberInfo.GetCustomAttributes(GetType(DisplayNameAttribute), False), DisplayNameAttribute())
If attr.Length > 0 Then
Return attr(0).DisplayName
Else
Exit For
End If
End If
Next
Return Nothing
End Function
That works fine, but it should search through both structures. Therefore, I changed the first lines into
Dim oType1, oType2 As Type
oType1 = GetType(Dimension.Derived)
oType2 = GetType(Dimension.Basis)
Dim colMemberInfo() As PropertyInfo = oType1.GetProperties And oType2.GetProperties
But this throws an exception that the And-Operator is not declared for PropertyInfo. Surely I can repeat the For-Each-loop for the another structure, but that's not the intention. What should I do to merge these PropertyInfos?
And is a boolean operator. It's for True/False values. You want to get a list of PropertyInfo from the two types, so try:
Dim properties as List(Of PropertyInfo) = New List(Of PropertyInfo)
properties.AddRange(oType1.GetProperties())
properties.AddRange(oType2.GetProperties())
I am trying to convert
Public Class TestClass
Public FirstName As String
End Class
To
Public Class AnotherClass
Public Property FirstName As String
End Class
I wrote a function that will convert the member of one class to member of another class, so if I pass some class type that has Public Property LastName AS String it will convert it to (for instance) AnotherClass Type variable and I will be able to get the value so I am happy here.
Public Shared Function ConvertModelToValidationDataModel(Of T)(ByVal oSourceObject As Object) As T
Dim oSourceObjectType As Type
Dim oSourceObjectProperties() As PropertyInfo
Dim oDestinationObjectProperties() As PropertyInfo
Dim oDestinationObject As Object
Dim oDestinationObjectType As Type
oDestinationObject = Activator.CreateInstance(Of T)()
oDestinationObjectType = GetType(T)
oDestinationObjectProperties = oDestinationObjectType.GetProperties
oSourceObjectType = oSourceObject.GetType()
oSourceObjectProperties = oSourceObjectType.GetProperties()
If Not oSourceObjectProperties Is Nothing Then
If oSourceObjectProperties.Count > 0 Then
For Each oDestinationObjectPropertyInfo As PropertyInfo In oDestinationObjectProperties
For Each oSourceObjectPropertyInfo As PropertyInfo In oSourceObjectProperties
If oDestinationObjectPropertyInfo.Name = oSourceObjectPropertyInfo.Name Then
oDestinationObjectPropertyInfo.SetValue(oDestinationObject, oSourceObjectPropertyInfo.GetValue(oSourceObject, Nothing))
End If
Next
Next
End If
End If
Return oDestinationObject
End Function
The problem is I want to pass TestClass (the variable FirstName is not a property but I want it to be converted to a property variable) and be able to convert it and get the value but for some reason it does not pass the value and obviously it looks like the function converts it to a non-property variable of another class - not the property variable like I want it to.
**
Short version:
**
When I pass in a class type that has property variables (Public Property FirstName As String) - I get back a class of another type, all the values are passed and converted to property variables.
When I pass in class type that has variables (Public FirstName As String) I am not able to get the value and it does not convert it to property variable.
Question: Why I am not able to get the value and convert it to a property variable when passing in a class type that has a non-property variable?
Solution
Thanks the guys in the comment section below for helping me visualize the fact that I was asking an object for the properties while object only had fields.
Here is the Updated Version of the function for those who interested
Public Shared Function ConvertModelToValidationDataModel(Of T)(ByVal oSourceObject As Object) As T
Dim oSourceObjectType As Type
Dim oSourceObjectFields() As FieldInfo
Dim oDestinationObjectProperties() As PropertyInfo
Dim oDestinationObject As Object
Dim oDestinationObjectType As Type
oSourceObjectType = oSourceObject.GetType()
oSourceObjectFields = oSourceObjectType.GetFields()
oDestinationObject = Activator.CreateInstance(Of T)()
oDestinationObjectType = GetType(T)
oDestinationObjectProperties = oDestinationObjectType.GetProperties
If Not oSourceObjectFields Is Nothing Then
If oSourceObjectFields.Count > 0 Then
For Each oSourceObjectFieldInfo As FieldInfo In oSourceObjectFields
For Each oDestinationObjectPropertyInfo As PropertyInfo In oDestinationObjectProperties
If oSourceObjectFieldInfo.Name = oDestinationObjectPropertyInfo.Name Then
oDestinationObjectPropertyInfo.SetValue(oDestinationObject, oSourceObjectFieldInfo.GetValue(oSourceObject))
End If
Next
Next
End If
End If
Return oDestinationObject
End Function
I am trying to create a class in VBA for the first time. I have looked up some solutions and I don't see anything wrong with my class, but when I run the test code, the integer returns correctly but the strings return empty:
Class
Property Let Name(strName As String)
pName = strName
End Property
Property Get Name() As String
Name = pName
End Property
Property Let Class(strClass As String)
pClass = strClass
End Property
Property Get Class() As String
Class = pClass
End Property
Property Let Aggro(intAggro As Integer)
pAggro = intAggro
End Property
Property Get Aggro() As Integer
Aggro = pAggro
End Property
Test Procedure
Sub ClassTest()
Dim Dog1 As New Critter
Dog1.Name = "Labrador"
Dog1.Class = "Canine"
Dog1.Aggro = 0
Debug.Print Dog1.Name 'returns ""
Debug.Print Dog1.Class 'returns ""
Debug.Print Dog1.Aggro 'returns 0
End Sub
The only thing you have wrong is you haven't define private variables to hold your property values. It appears the integer is working because Integer initializes to 0, and you are 'setting' the value to 0. Just add this to the top of your class and try again:
Private pName as String
Private pClass as String
Private pAggro as Integer
:D
I'm trying to create a custom property in an excel sheet, then retrieve its value. This is fine when I don't use an empty string, i.e. "". When I use the empty string, I get this error:
Run-time error '7':
Out of memory
Here's the code I'm using:
Sub proptest()
Dim cprop As CustomProperty
Dim sht As Worksheet
Set sht = ThisWorkbook.Sheets("control")
sht.CustomProperties.Add "path", ""
For Each cprop In ThisWorkbook.Sheets("control").CustomProperties
If cprop.Name = "path" Then
Debug.Print cprop.Value
End If
Next
End Sub
The code fails at Debug.Print cprop.value. Shouldn't I be able to set the property to "" initially?
With vbNullChar it works, sample:
Sub proptest()
Dim sht As Worksheet
Set sht = ThisWorkbook.Sheets("control")
' On Error Resume Next
sht.CustomProperties.Item(1).Delete
' On Error GoTo 0
Dim pathValue As Variant
pathValue = vbNullChar
Dim pathCustomProperty As CustomProperty
Set pathCustomProperty = sht.CustomProperties.Add("path", pathValue)
Dim cprop As CustomProperty
For Each cprop In ThisWorkbook.Sheets("control").CustomProperties
If cprop.Name = "path" Then
Debug.Print cprop.Value
End If
Next
End Sub
I think from the comments and the answer from Daniel Dusek it is clear that this cannot be done. The property should have at least 1 character to be valid, an empty string just isnt allowed and will give an error when the .Value is called.
So you Add this property with a length 1 or more string and you Delete the property again when no actual value is to be assigned to it.
As already mentioned it is not possible to set empty strings.
An easy workaround is to use a magic word or character, such as ~Empty (or whatever seems proof enough for you):
Dim MyProperty As Excel.CustomProperty = ...
Dim PropertyValue As String = If(MyProperty.Value = "~Empty", String.Empty, MyPropertyValue)
A slightly more expensive workaround but 100% safe is to start all the values of your custom properties with a character that you then always strip off. When accessing the value, systematically remove the first character:
Dim MyProperty As Excel.CustomProperty = ...
Dim PropertyValue As String = Strings.Mid(MyProperty.Value, 2)
You can write an extension to make your life easier:
<System.Runtime.CompilerServices.Extension>
Function ValueTrim(MyProperty as Excel.CustomProperty) As String
Return Strings.Mid(MyProperty.Value, 2)
End Function
Now you can use it like this: Dim MyValue As String = MyProperty.ValueTrim
Use a reversed principle when you add a custom property:
<System.Runtime.CompilerServices.Extension>
Function AddTrim(MyProperties As Excel.CustomProperties, Name As String, Value As String) as Excel.CustomProperty
Dim ModifiedValue As String = String.Concat("~", Value) 'Use ~ or whatever character you lie / Note Strig.Concat is the least expensive way to join two strings together.
Dim NewProperty As Excel.CustomProperty = MyProperties.Add(Name, ModifiedValue)
Return NewProperty
End Function
To use like this: MyProperties.AddTrim(Name, Value)
Hope this helps other people who come across the issue..
Based on the other answers and some trial and error, I wrote a class to wrap a Worksheet.CustomProperty.
WorksheetProperty:Class
Sets and Gets the value of a Worksheet.CustomProperty and tests if a Worksheet has the CustomProperty
VERSION 1.0 CLASS
Attribute VB_Name = "WorksheetProperty"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
'#Folder("Classes")
'#PredeclaredId
Option Explicit
Private Type TMembers
Name As String
Worksheet As Worksheet
End Type
Private this As TMembers
Public Property Get Create(pWorksheet As Worksheet, pName As String) As WorksheetProperty
With New WorksheetProperty
Set .Worksheet = pWorksheet
.Name = pName
Set Create = .Self
End With
End Property
Public Property Get Self() As WorksheetProperty
Set Self = Me
End Property
Public Property Get Worksheet() As Worksheet
Set Worksheet = this.Worksheet
End Property
Public Property Set Worksheet(ByVal pValue As Worksheet)
Set this.Worksheet = pValue
End Property
Public Property Get Name() As String
Name = this.Name
End Property
Public Property Let Name(ByVal pValue As String)
this.Name = pValue
End Property
Public Property Get Value() As String
Dim P As CustomProperty
For Each P In Worksheet.CustomProperties
If P.Name = Name Then
Value = P.Value
Exit Property
End If
Next
End Property
Public Property Let Value(ByVal pValue As String)
Delete
Worksheet.CustomProperties.Add Name:=Name, Value:=pValue
End Property
Public Property Get hasCustomProperty(pWorksheet As Worksheet, pName As String) As Boolean
Dim P As CustomProperty
For Each P In pWorksheet.CustomProperties
If P.Name = pName Then
hasCustomProperty = True
Exit Property
End If
Next
End Property
Public Sub Delete()
Dim P As CustomProperty
For Each P In Worksheet.CustomProperties
If P.Name = Name Then
P.Delete
Exit For
End If
Next
End Sub
Usage
I have several properties of my custom Unit class return a WorksheetProperty. It makes it really easy to sync my database with my worksheets.
Public Function hasMeta(Ws As Worksheet) As Boolean
hasMeta = WorksheetProperty.hasCustomProperty(Ws, MetaName)
End Function
Public Property Get Id() As WorksheetProperty
Set Id = WorksheetProperty.Create(this.Worksheet, "id")
End Property
Public Property Get CourseID() As WorksheetProperty
Set CourseID = WorksheetProperty.Create(this.Worksheet, "course_id")
End Property
Public Property Get Name() As WorksheetProperty
Set Name = WorksheetProperty.Create(this.Worksheet, "unit_name")
End Property
Simple Usage
'ActiveSheet has a CustomProperty
Debug.Print WorksheetProperty.hasCustomProperty(ActiveSheet, "LastDateSynced")
'Set a CustomProperty
WorksheetProperty.Create(ActiveSheet, "LastDateSynced").Value = Now
'Retrieve a CustomProperty
Debug.Print WorksheetProperty.Create(ActiveSheet, "LastDateSynced").Value
In VB.NET, how can I convert the following string into some kind of key/value type such as a Hashtable, Dictionary, etc?
"Name=Fred;Birthday=19-June-1906;ID=12345"
I want to extract Birthday or ID without having to split the string into an array.
EDIT: I'd prefer not to split the string into an array in case the format of the string changes later. I don't have control over the string. What if someone switches the order around or adds another element?
I’m currently unable to test this, lacking a VB compiler, but the following solution should also work, and it has the advantage of not requiring an explicit loop. It uses the Linq method ToDictionary and two nested Split operations:
Dim s = "Name=Fred;Birthday=19-June-1906;ID=12345"
Dim d = s.Split(";"c).Select(Function (kvp) kvp.Split("="c)) _
.ToDictionary( _
Function (kvp) kvp(0), _
Function (kvp) kvp(1))
First, we split on the outer delimiter (i.e. the semi-colon). From the resulting array, we select by splitting again, this time on =. The resulting array of arrays is converted to a dictionary by specifying that the first item is to become the key and the second is to become the value (the identifier kvp stands for “key-value pair”).
Since I can’t check the exact VB syntax and the above may contain subtle errors, here is the equivalent C# code (tested for correctness):
var s = "Name=Fred;Birthday=19-June-1906;ID=12345";
var d = s.Split(';').Select(kvp => kvp.Split('='))
.ToDictionary(kvp => kvp[0], kvp => kvp[1]);
Not sure why you don't want to split it. If you're sure there won't be any extra = or ; then you could just do:
Dim s As String = "Name=Fred;Birthday=19-June-1906;ID=12345"
Dim d As New Dictionary(Of String, String)
For Each temp As String In s.Split(";"c)
Dim index As Int32 = temp.IndexOf("="c)
d.Add(temp.Substring(0, index), temp.Substring(index + 1))
Next
Which might not be beautiful, but is very easy to understand.
input.Split(";"c) returns an array of key/value:
{ "Name=Fred", "Birthday=19-June-1906" , "ID=12345" }
so pair.Split("="c) returns { "Name", "Fred" } etc
If you want an alternative to doing a String.Split; there is always Regular Expressions as an alternative:
Dim map As Dictionary(Of String, String) = New Dictionary(Of String, String)
Dim match As Match = Regex.Match("Name=Fred;Birthday=19-June-1906;ID=12345", "(?<Name>[^=]*)=(?<Value>[^;]*);?")
While (match.Success)
map.Add(match.Groups("Name").Value, match.Groups("Value").Value)
match = match.NextMatch()
End While
The regular expression itself could be beefed up to better handle whitespace between key/value's and pair's but you hopefully get the idea. This should only pass through the string once to build up a string dictionary of keys and values.
Dim persSeparator as string=";"
Dim keyValSeparator as string="=";
Dim allPersons As New Dictionary(Of String, Person)
Dim str As String = "Name=Fred;Birthday=19-June-1906;ID=12345"
Dim parts As New List(Of String)(str.Split(persSeparator.ToCharArray)) 'why dont want you to split this string??
Dim person As New Person
For Each part As String In parts
Dim keyValue() As String = part.Split(keyValSeparator.toCharArray())
Select Case keyValue(0).ToUpper
Case "ID"
person.ID = keyValue(1)
Case "NAME"
person.Name = keyValue(1)
Case "BIRTHDAY"
person.BirthDay= keyValue(1)
End Select
Next
If Not allPersons.ContainsKey(person.ID) Then
allPersons.Add(person.ID, person)
End If
Public Class Person
Private _name As String
Private _birthday As String
Private _id As String = String.Empty
Public Sub New()
End Sub
Public Sub New(ByVal id As String)
Me._id = id
End Sub
Public Sub New(ByVal id As String, ByVal name As String)
Me._id = id
Me._name = name
End Sub
Public Sub New(ByVal id As String, ByVal name As String, ByVal birthday As String)
Me._id = id
Me._name = name
Me._birthday = birthday
End Sub
Public Property ID() As String
Get
Return Me._id
End Get
Set(ByVal value As String)
Me._id = value
End Set
End Property
Public Property Name() As String
Get
Return Me._name
End Get
Set(ByVal value As String)
Me._name = value
End Set
End Property
Public Property BirthDay() As String
Get
Return Me._birthday
End Get
Set(ByVal value As String)
Me._birthday = value
End Set
End Property
Public Overrides Function Equals(ByVal obj As Object) As Boolean
If TypeOf obj Is Person AndAlso Not obj Is Nothing Then
Return String.Compare(Me._id, DirectCast(obj, Person).ID) = 0
Else : Return False
End If
End Function
End Class
If you were just wanting to extract the birthday and ID from the string and place as a value pair in some sort of dictionary, for simplicity I would use regular expressions and then a generic dictionary (of string, valuepair structure). Something like this:
Imports System.Text.RegularExpressions
Imports System.Collections.Generic
Sub Main()
Dim Person As New Dictionary(Of String, ValuePair)
Dim s As String = "Name=Fred;Birthday=19-June-1906;ID=12"
Dim r As Regex = New Regex("Name=(.*);Birthday=(.*);ID=(.*$)")
Dim m As Match = r.Match(s)
Person.Add(CStr(m.Groups(1).Value), _
New ValuePair(CDate(m.Groups(2).Value), CInt(m.Groups(3).Value)))
Console.WriteLine(Person("Fred").Birthday.ToString)
Console.WriteLine(Person("Fred").ID.ToString)
Console.Read()
End Sub
Friend Structure ValuePair
Private _birthday As Date
Private _ID As Int32
Public ReadOnly Property ID() As Int32
Get
Return _ID
End Get
End Property
Public ReadOnly Property Birthday() As Date
Get
Return _birthday
End Get
End Property
Sub New(ByVal Birthday As Date, ByVal ID As Int32)
_birthday = Birthday
_ID = ID
End Sub
End Structure