CODEWITHSUNDEEP
asp.netdatabasegridview
yrazlik
yrazlik

Reputation: 10777

How to fill a gridview from a list in asp.net?

I have a gridview in my page and i show some search results in it. Here is how i do it:

int row = -1;
        int.TryParse(e.CommandArgument as string, out row);

        GridViewRow gdrow = instCourses.Rows[row];

        // *** Get the underlying data item - in this case a DataRow
        DataRow dr = ((DataTable)this.instCourses.DataSource).Rows[gdrow.DataItemIndex];

        // *** Retrieve our context
        string courseCode = dr["CourseCode"].ToString();
        string courseNumber = dr["CourseNumber"].ToString();
        string term = dr["Term"].ToString();
        SqlConnection con = new SqlConnection();
        con.ConnectionString = Userfunctions.GetConnectionString();
        con.Open();
        SqlCommand cmd=new SqlCommand("SELECT RegisterTable.StudentID, StudentTable.Name, StudentTable.Surname FROM RegisterTable JOIN StudentTable ON RegisterTable.StudentID = StudentTable.ID WHERE RegisterTable.CourseCode = @courseCode AND RegisterTable.Term = @term AND RegisterTable.CourseNumber = @courseNumber",con);
        cmd.Parameters.AddWithValue("@courseCode", courseCode);
        cmd.Parameters.AddWithValue("@courseNumber", courseNumber);
        cmd.Parameters.AddWithValue("@term", term);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);
        studList.DataSource = dt;
        studList.DataBind();
        Label1.Visible = true;
        Label1.Text = "Students who are registered to "+courseCode+ " " + courseNumber +" are listed below:";

But i have already done the same query before, and kept the results in a list, let's say the name of the list is searchResults. My question is, instead of querying the database again to fill the table, can i use the items in that list to fill the gridview? Or should i use any other thing instead of gridview to do this?

Thank you

Upvotes: 1

Views: 2363

Answers (2)

Josh Darnell
Josh Darnell

Reputation: 11433

I misunderstood what you were asking. You can use a List<T> of objects as your datasource in the same way that you are using the DataTable in your example above. You just have to make sure that you expose the class-variables that you want your GridView to see as public properties - like this:

public class Course
{
    public string courseCode { get; set; }
    public string courseName { get; set; }
    public string courseNumber { get; set; }

    //...the rest of your class code...//
}

If you are going to be reusing that DataTable, I would just store it in the Session. So where you set it to your datasource:

DataTable dt = new DataTable();
da.Fill(dt);
studList.DataSource = dt;

Also, add it to the Session:

Session["mySearchResults"] = dt;

Then you can reference that to populate your other list:

myOtherList.DataSource = (DataTable)Session["mySearchResults"];
myOtherList.DataBind();

Note that if this DataTable is really huge, or if you're going to have a lot of users accessing this application at once, this approach might bring problems (resource-wise on your web server). But it works as a simple solution.

Upvotes: 1

Ronald
Ronald

Reputation: 2120

You can use your list (IEnumerable) as the datasource of your gridview. No need to query again

    studList.DataSource = searchResults;
    studList.DataBind();

Upvotes: 1

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