1

So I haven't used ASP.NET for three years or so and I'm really rusty on it. My old code isn't available to me for review (at an old company). This question should be pretty basic, but I can't find any good or reliable or not-super-old resources on the issue, so I'm asking here.

Can I get a general overview of databinding again? I remember it being really useful for select boxes, etc., but I don't really remember how it works. Maybe a good ASP.NET tutorial in general, because I don't remember how it handles POST requests or anything like that really either. Should I just try ASP.NET MVC?

Relatedly, suppose I have a public variable in my codebehind page. Right now I am accessing it by saying Page.DataBind() at the end of the page load function and then running <%# variable %> in the ASPX, but that's not how I remember doing it before and I reckon that it's not very good practice. What's the best way to display variables from codebehind?

Improve this question
1
  • the convention is that you accept the answer "which answer is the most helpful to you" -- right from the FAQ. The reputation system is a major driving force in yielding quality answers. If you don't participate within the community conventions, you're not helping build the community and generate better answers. To your other point, more generalized questions should be Community Wiki. Commented Jul 26, 2010 at 18:20

2 Answers 2

Reset to default
1

Databinding in general (at least in the WebForms model) is mostly a case of assigning fields to be displayed, setting the DataSource property to a suitable object that contains those fields e.g. a DataReader, DataTable, a Collection, and calling the DataBind method. So for your select case, you'd put an <asp:dropdownlist runat="server" id="MyDropDownList"> in the markup for the page, and then in the code

DataSet myDataSet;

myDataSet = someDataMethod();

MyDropDownList.DataTextField = fieldname;
MyDropDownList.DataValueField = fieldname;
MyDropDownList.DataSource = myDataSet;
MyDropDownList.DataBind();

Or you can avoid writing that kind of code and do it in the markup if you use a DataSource control e.g. <asp:SqlDataSource>, <asp:ObjectDataSource>

<asp:SqlDataSource runat="server" id="MySqlDataSource" ConnectionString="aConnectionString" SelectCommand="MyStoredProcName" SelectCommandType="StoredProcedure"  />
<asp:dropdownlist runat="server" id="MyDropDownList" DataSourceId="MySqlDataSource" DataTextField="fieldname" DataValueField="fieldname">

For putting your variable on a page, the way you might have done it before is to have a label or textbox on the page, that in your code-behind you assign your variable to the Text property e.g.

<asp:label runat="server" id="MyLabel" />

MyLabel.Text = myVariable.ToString();

Postbacks: you can test the IsPostback property of a page in code-behind to determine if it's a postback or not. After the Page_Load method, other methods will fire if you've defined them e.g. SelectedIndexChanged for a DropDownList.

Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

0

I really wanted to answer this question with examples and code etc.. but I would just be rehashing information that has been on the web for years and been explained in blogs and articles countless times. You can start with this article which explains almost everything you need to know.

I have bolded the ones that I think are important to note that some my skim over.

  1. <%# %> Syntax
  2. Page.DataBind() versus Control.DataBind()
  3. Data-bound list controls
  4. Repeater control
  5. DataList control
  6. DataGrid control
  7. Accessing data
  8. DataSet class
  9. DataReader class
  10. Binding in list control templates
  11. DataBinder.Eval method
  12. Explicit casting
  13. ItemDataBound event

As for learning MVC over webforms, that is whole different story. They both have pluses and minuses depending on your time, what you NEED to know and what portions of the project are important. Both techs can accomplish the same thing as they are all ASP.NET at their core, just different approaches so you will be fine either way.

Improve this answer

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.