System.ArgumentException: String value can not be converted to a date - asp.net

Question

I have a web form that uses an Ajax date calendar. This works fine. The problem that i have is that when i submit my form i get the following message.
'String value can not be converted to a date' .AgendaDate = New SmartDate(txtAgendaDate.Text)
Here is my web form that holds the calendar and the associated text box...
<td>
<asp:TextBox ID="txtAgendaDate" runat="server" ForeColor="Black" ></asp:TextBox>
</td>
<td>
<asp:ImageButton runat="Server" ID="ImageButton1" ImageUrl="~/images/calendarpic.png"
AlternateText="Click here to display calendar" />
<cc1:calendarextender ID="CalendarExtender1" runat="server"
TargetControlID="txtAgendaDate" PopupButtonID="ImageButton1" >
</cc1:calendarextender>
</td>
I have a class with the associated properties on it for the web form. The rest of the fields work and submit data to the database except the textfield for the ajax calendar.
Here is my stripped down version for the code for the class and the txtAgendaDate code...
#Region " Agenda Variables "
'Declare Variables and data types and set default values
Private mAgendaID As Integer = 0
Private mOrganiser As String = ""
Private mMeeting As String = ""
Private mAgendaDate As SmartDate = New SmartDate()
#End Region
#Region " Constructors "
Public Sub New()
End Sub
Public Sub New(ByVal reader As SafeDataReader)
' Public Sub New(ByVal reader As SQLDataReader)
'Combine variables & property types
With reader
mAgendaID = .GetInt32("AgendaID")
mOrganiser = .GetString("Organiser")
mMeeting = .GetString("Meeting")
mAgendaDate = .GetSmartDate("AgendaDate")
End With
End Sub
#End Region
#Region "Properties"
'Define form field properies so that they can be used when adding the data to the database on the add button is pressed.
Public Property AgendaID() As Integer
Get
Return mAgendaID
End Get
Set(ByVal Value As Integer)
mAgendaID = Value
End Set
End Property
Public Property Organiser() As String
Get
Return mOrganiser
End Get
Set(ByVal value As String)
mOrganiser = value
End Set
End Property
Public Property Meeting() As String
Get
Return mMeeting
End Get
Set(ByVal value As String)
mMeeting = value
End Set
End Property
Public Property AgendaDate() As SmartDate
Get
Return mAgendaDate
End Get
Set(ByVal Value As SmartDate)
mAgendaDate = Value
End Set
End Property
#End Region
End Class
Here is my command that looks connects to the DB and at the stored procedure and also has the parameters.
Public Class Agenda_TempDAL
Public Shared Function AddAgenda_Temp(ByVal Agenda_Temp As Agenda_Temp) As Integer
'Declare i as integer as 0
Dim iAgendaID As Integer = 0
'Database conn, this is linked to the web config file .AppSettings
Using dbconnection As New SqlConnection(ConfigurationManager.AppSettings("dbconnection"))
dbconnection.Open()
'Command to state the stored procedure and the name of the stored procedure
Using dbcommand As SqlCommand = dbconnection.CreateCommand
With dbcommand
.CommandType = CommandType.StoredProcedure
.CommandText = "Stored_Proc_Name"
'Create parameter for AgendaID and output
Dim oParam As New SqlParameter
oParam.ParameterName = "#AgendaID"
oParam.Direction = ParameterDirection.Output
oParam.SqlDbType = SqlDbType.Int
'Create parameters for the remaining fields
.Parameters.Add(oParam)
.Parameters.AddWithValue("#Organiser", Agenda_Temp.Organiser)
.Parameters.AddWithValue("#Meeting", Agenda_Temp.Meeting)
.Parameters.AddWithValue("#AgendaDate", Agenda_Temp.AgendaDate.DBValue)
'Simply execute the query
dbcommand.ExecuteNonQuery()
End With
End Using
End Using
'Need to return the agendaID as an integer.
Return iAgendaID
End Function
End Class
And here is the code behind the button ion the web page. This is the page that causes the error based on the property / field. The problem lies on this line...
.AgendaDate = New SmartDate(txtAgendaDate.Text)
The whole code for the button is here...
Protected Sub btnAddAgendaTemplate_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddAgendaTemplate.Click
'This works alongside the Class named Agenda_Temp which has the properties and DB connection assigned to it for each web form field.
Dim oAgenda_Temp As New Agenda_Temp
'Within the object Agenda_Temp Class use the properties defined.
'They are required to be defined in the Agenda_Temp/ app code so we can use them within here.
With oAgenda_Temp
.Organiser = txtOrganiser.Text
.Meeting = txtMeeting.Text
.AgendaDate = New SmartDate(txtAgendaDate.Text)
'Within the object Agenda_Temp class use the defined DAL which includes all the DC connect and stored procedures.
oAgenda_Temp.AgendaID = Agenda_TempDAL.AddAgenda_Temp(oAgenda_Temp)
End With
End Sub
End Class
I understand that its telling me that the string value cannot be converted to a date but i don't know hoe to resolve this as i am new to .net 2010?
Any help much appreciated.

Answer 1

Convert the string to a date before newing it:
From MSDN:
string date = "01/08/2008";
DateTime dt = Convert.ToDateTime(date);
Your's would become
DateTime dt = Convert.ToDateTime(txtAgendaDate.Text)
Then pass the date to your SmartDate constructor:
oAgenda_Temp.AgendaDate = new SmartDate(dt)
The final result:
With oAgenda_Temp
.Organiser = txtOrganiser.Text
.Meeting = txtMeeting.Text
.AgendaDate = New SmartDate(Convert.ToDateTime(txtAgendaDate.Text))
'Within the object Agenda_Temp class use the defined DAL which includes all the DC connect and stored procedures.
oAgenda_Temp.AgendaID = Agenda_TempDAL.AddAgenda_Temp(oAgenda_Temp)
End With

Answer 2

As others have pointed out, you need to convert the input value to a DateTime. I don't know what the SmartDate() function is doing, but the error message clearly indicates that the value cannot be converted to a date.
Secondly, I would add some validation to make sure that the input is valid before you submit the page. Use the RequiredFieldValidator and CompareValidator or RegularExpressionValidator:
<asp:TextBox ID="txtDate" runat="server" ... />
<asp:RequiredFieldValidator ID="reqDate" runat="server" ErrorMessage="Required" Display="Dynamic" ControlToValidate="txtDate"></asp:RequiredFieldValidator>
<asp:RegularExpressionValidator ID="regDate" runat="server" ControlToValidate="txtDate" ErrorMessage="Please enter a valid date in the format (mm/dd/yyyy)" ValidationExpression="^(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d$"></asp:RegularExpressionValidator>