Databinding to text boxes

[anusha007khader]

I have no idea about how to bind data to text box.

I have a user details aspx form and i wnt to display the data entered by the user before to be displayed in the text box when user clicking the Edit profile button.

i.e the values from sql database should be bounded with the text boxes. There are more than 27 text boxes in the user profile form.

[Frinavale]

I'm not sure where to start.
Could you please post what you have tried so far to solve the problem so that we have something to help you with?

Thanks

-Frinny

[tlhintoq]

Original Poster: I don't know how to use a search engine. Could someone do it for me?

http://www.lmgtfy.com/?q=C%23+databind+textbox&ie=UTF-8&oe=UTF-8

[anusha007khader]

I'm not sure where to start.
Could you please post what you have tried so far to solve the problem so that we have something to help you with?

Thanks

-Frinny

Thanks Frinny for your response


In short i just want to bind some data with the text boxes in my aspx form. But the data which i need to bind with the text boxes is from my sql database .

Hope tht its clear to u, there are 27 text boxes in my page.

Waiting for your help...

[Frinavale]

I'm still not sure where to start helping you.
If I were you I'd create a class used to represent your user.
I would retrieve the user's details from the database.
I would use reflection to loop through the properties of the user class to create textboxes used to display and gather the user information.

-Frinny

[DaveRook]

At a guess

<asp:Textbox ID="id" runat="server" text='<%#Eval(" DatabaseColumnN ame") %>' /> (note single quotes)

This assumes you've used set up a dataset

Dave

[Frinavale]

See that's the thing...maybe I'm just lazy or something but dragging 27 TextBoxes onto the page and naming them all and then binding to them...

Seems like too much work.


It'd be easier to create a ListOf TextBoxes...
Use Reflection to loop through all of the User's properties.
Each property you find create a TextBox (setting the TextBox's ID = the property name so that you can reference it later). Add the newly created TextBox to the ListOf TextBoxes and to a control (like a panel) that will contain the user's information. (Do all of this in your Page Init Event).

Then in your page load event, the first time the page is loaded...call a method on your user class to "get" the user's information. This will populate the class with data....

Now typically I just use reflection again at this point to populate the TextBoxes with text....but I see no reason why you can't set up the binding to the properties when you're dynamically creating the TextBoxes. (I've never tried this, so it might be harder than I think...)

See there's the other thing (lazieness coming out again) but I've created a "Field" user control that has a Textbox and a "Prompt" (a label control) used for describing the what the TextBox represents. I dynamically add these user controls to the page instead of just TextBoxes (since it makes more sense).

Like I said I'm a little lazy and don't like it when some-thing that I need to display/retrieve data for has 100+ fields that I need to interact with...it's just easier to reflect than do this manually.

-Frinny

[DaveRook]

Frinny

I don't think you appreciate how valuable posts like yours are! Thank you. By doing so, you're giving people (including myself) an insight into best practices, how to approach problems etc.

Thank you

Dave

[Frinavale]

I'm not sure it's best-practices but over time I've found my programming style is changing to be a lot more abstract...work ing at a level where I don't care what the property names are when displaying/retrieving data from the user.


Normally I don't just give out my thoughts on the problems that I'm helping with because I've learned that my approach to solving problems is vastly different than the people asking about the problem. I find it's easier to get insight into how the user thinks to give them a solution that they can easily understand and is their style of programming.

Here is a snippet of what I was talking about earlier...the code is clean, and simple and easy to use/maintain.

I have a Web User Control that has a Label to display a prompt/text and a TextBox that is used to display and gather data. This control is called "FieldUserContr ol" for simplicity and has 2 important properties: the Text property (which gets and sets the TextBox.Text property) and the Prompt property (which gets and sets the Label.Text property). It has other properties for styling etc but we won't get into them because I want to keep my point clear.

Now say we have a page (or user control) and we want to let the user see/edit a bunch of Text Properties of a class "XYZ".

First of all I would declare a ListOf FieldUserContro ls (at Page level scope), used as a container for all the FieldUserContro ls required to let the user see/edit the XYZ's properties.

Then in the Page Init Event I would use Reflection (so you need to import the namespace) to rip through the all the Properties in XYZ, create a FieldUserContro l for each one, give the FieldUserContro l the ID that matches the property name, and add the FieldUserContro l to the page and to the ListOf FieldUserContro ls:

Imports System.Reflection
'......
Private _xyzFields As List(Of FieldUserControl) 'a container for all the FieldUserControls required to display/retrieve data for XYZ
Private urlToFieldControl As String = "~/FieldUserControl.ascx" 'Path to the FieldUserControl

Private Sub MyPage_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
  _xyzFields= New List(Of FieldUserControl)
  InstantiateXyzFields()
End Sub

Private Sub InstantiateXyzFields() 
  'Grabbing all of the properties for class XYZ
  Dim xyzFieldProperties() As PropertyInfo = GetType(XYZ).GetProperties

  'Ripping through each XYZ property
  For i As Integer = 0 To xyzFieldProperties.Length - 1
    'Creating a FieldUserControl control to represent the property
    Dim f As FieldUserControl= CType(Page.LoadControl(_urlToFieldControl), FieldUserControl)
    
   'Getting the property information
    Dim pi As PropertyInfo = xyzFieldProperties(i)

   'Setting the ID of the FieldUserControl to the property name
    f.ID = pi.name
  
   'Setting the Prompt for the FieldUserControl to the property name
    f.Prompt = pi.name

    'Adding the FieldUserControl control to a Panel that is on the page where we want
    'the FieldUserControls to be displayed 
    PanelThatContainsXYZsFields.Controls.Add(f)
   
    'Adding the field control to the list of fields for later use
    _xyzFields.Add(f)
  Next
End Sub

Now we have a FieldUserContro l control (a Label-TextBox pair) for every property that is part of the XYZ class added to the page....prompt is set with the name of the property so that the user can identify what it is (what's really nice is that you can set up resources that contain prompts in the languages that your application supports...usin g the property names as the Key value for each prompt...that way you can retrieve the translated text/user friendly prompt for each property easily)

At this time we have FieldUserContro ls added to the page with prompts but the TextBoxes don't contain any information. Say XYZ has a method called "Populate" that goes to the database, retrieves the information, and populates the class's properties with the data retrieved.

I would call this method in the Page Load event only if isPostback=fals e (the first time the page is loaded). Then I would loop through all of the properties for the class and set the corresponding FieldUserContro l's Text property:

  
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
  If IsPostBack = False Then
    DisplayXYZData()    
  End If
End Sub

Private Sub DisplayXYZData()
  'Creating an instance of the XYZ class
  Dim instanceOfXYZ As New XYZ

  'Populating the instance of the class with data
  instanceOfXYZ.Populate()

  'Grabbing all of the properties for class XYZ
  Dim xyzFieldProperties() As PropertyInfo = GetType(XYZ).GetProperties

  'Ripping through each XYZ property
  For i As Integer = 0 To xyzFieldProperties.Length - 1   
   'Getting the property information
    Dim pi As PropertyInfo = xyzFieldProperties(i)

    'Getting the property name & storing it into a string (for Lambda expression to work nicely)
    Dim propertyName As String = pi.Name

    'Using the Array.Find method to retrieve the FieldUserControl that corresponds with the property
    'Note that I'm using a Lambda expression for simplicity sake
    Dim f As FieldUserControl = Array.Find(_xyzFields.ToArray, Function(x) String.Compare(x.ID,propertyName)=0)

    'Making sure that the Array.Find method worked...that f exists before trying to use it
    If f IsNot Nothing Then
      'Setting the FieldUserControl's Text property with the value of the property
      'that is in the instanceOfXYZ object
       f.Text = pi.GetValue(instanceOfXYZ,Nothing)
    End If
  Next
End Sub

Tada: done.
We are displaying all properties of a class (whether it be 1 or 1000) on the screen with a Label for each property and a TextBox for each property. The TextBoxes are displaying data for the properties....w hat more could you ask for?

Oh retrieveing data is just as simple: get all the properties for the class, get the corresponding FieldUserContro l for the property...use the property Info's SetValue method to set the class with the data in the TextBox.

Private Sub RetrieveXYZData()
  'Creating an instance of the XYZ class
  Dim instanceOfXYZ As New XYZ

  'Grabbing all of the properties for class XYZ
  Dim xyzFieldProperties() As PropertyInfo = GetType(XYZ).GetProperties

  'Ripping through each XYZ property
  For i As Integer = 0 To xyzFieldProperties.Length - 1   
   'Getting the property information
    Dim pi As PropertyInfo = xyzFieldProperties(i)

    'Getting the property name & storing it into a string (for Lambda expression to work nicely)
    Dim propertyName As String = pi.Name

    'Using the Array.Find method to retrieve the FieldUserControl that corresponds with the property
    'Note that I'm using a Lambda expression for simplicity sake
    Dim f As FieldUserControl = Array.Find(_xyzFields.ToArray, Function(x) String.Compare(x.ID,propertyName)=0)

    'Making sure that the Array.Find method worked...that f exists before trying to use it
    If f IsNot Nothing Then
      'Setting the instanceOfXYZ's property with the value of the Text property
      'that is in the corresponding FieldUserControl object
      pi.SetValue(instanceOfXYZ, f.Text, BindingFlags.GetField, Nothing, Nothing, Nothing)
    End If
  Next
End Sub

-Frinny