ASP.Net datasource navigation

Question

I've been looking for a while, and didn't find a proper solution; I'm trying to search in a DataSet (which is a source of a gridView) which consists of usernames & details in an ASP.Net page.

If the user wants to find a specific row, he needs to insert the username, and press a button. Then, I want to change the dataset which is saved on the cache - I want it to contain that specific row the user was searching for.

However, when I change the dataset (set it to contain only one row) I get the following error:

A field or property with the name 'Username' was not found on the selected data source.

Am I doing anything wrong?

Here's the code:

protected void Search_Click(object 
        sender, EventArgs e)
    {
        DataRow myRow = findRow(((DataSet)Cache["Users"]).Tables[0], userSearched.Text);
        if (myRow == null)
        {
            ResponseLabel.ForeColor = System.Drawing.Color.Red;
            ResponseLabel.Text = "User not found.";
            return;
        }
        ResponseLabel.ForeColor = System.Drawing.Color.Green;
        ResponseLabel.Text = "There you go.";
        DataSet newDs = new DataSet();
        DataTable newDt = new DataTable();
        newDt.ImportRow(myRow);
        newDs.Tables.Add(newDt);
        Cache["Users"] = newDs;
        UpdateSource(); // Updating the source after each iteration
        }

findrow():

private DataRow findRow(DataTable View, string searchValue, int index = 0)
    {
        foreach (DataRow row in View.Rows)
        {
            if (row.ItemArray[index].Equals(searchValue))
            {
                return row;
            }
        }
        return null;
    }

Relevant part in the GridView:

<Columns>
        <asp:BoundField DataField="Username" HeaderText="Username" 
            SortExpression="Username" />
        <asp:BoundField DataField="TimeJoined" HeaderText="Joined" 
            SortExpression="TimeJoined" />
        <asp:BoundField DataField="Email" HeaderText="Email" SortExpression="Email" />
        <asp:CheckBoxField DataField="Banned" HeaderText="Banned" 
            SortExpression="Banned" />
        <asp:CheckBoxField DataField="Admin" HeaderText="Admin" 
            SortExpression="Admin" />
        <asp:CommandField HeaderText="Options" ShowEditButton="True" 
            ShowHeader="True" />
    </Columns>

Page load:

protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            if (Cache["Users"] == null)
            {
                UsersView.DataSource = DbManager.getUsersView(); // database stuff. It worked pretty well before.
                Cache["Users"] = UsersView.DataSource;
            }
            else
            {
                UsersView.DataSource = (DataSet)Cache["Users"];
            }
            UsersView.DataBind(); // I get the error here.
        }
    }

If you need anything else, let me know. Thanks in advance!

TAMTAM · Accepted Answer · 2015-03-08 08:38:34Z

1

I believe you are losing the DataTable schema when you recreate it in Search_Click, try explicitly declaring the column names.

Btw, have you tried the DataTable Select method (https://msdn.microsoft.com/en-us/library/y06xa2h1.aspx) or a DataView (https://msdn.microsoft.com/en-us/library/bb669073%28v=vs.110%29.aspx) ?

answered Mar 8, 2015 at 8:38

TAMTAM

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2 Comments

A. Abramov Over a year ago

What do you mean by that? can you give an example (given the columns in the example)

TAMTAM Over a year ago

Here's a nice example: msdn.microsoft.com/en-us/library/hfx3s9wd%28v=vs.110%29.aspx

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