How to use different editors depending on some row data?

[gmendez]

Hello,

I'm very new to ASP.Net and RadControls for ASP.Net.
I'm creating a web application intended to help the user building a SQL Query for a given table. The user needs to specify filters for the query for a set of pre-selected fields.
I decided to use a RadGridView for letting the user entering this information. Each row represents a filter, and those filters include a comparison operator and a value to compare against it.
I have already managed for populating a dropdown column dinamically with the possible set of operators one could apply for each field depending on it's data type. Now I'd like to be able to decide at runtime for each row what editor to use (depending on the field's data type too) for letting the user enter the value. Please note that when I talk about a field I'm talking about it's logical representation: a row, not a column.
Is it possible at all? Any help will be very apreciated.
Thanks in advance,

Gonzalo

[NLV]

Hello Gonzalo

I would simply achieve that by trapping the event 'ItemCreated'. Put a GridTemplateColumn with an empty panel in it. During the ItemCreated event trap the panel creating for each row and based on the data on another column add your dynamic control into the panel.

Note: There could be better ways

Regards
NLV.

[Tsvetoslav]

Hi Gonzalo,

Raghavendra's approach is viable but I'd like to make one small correction: if you need to use data from other columns in order to programmatically create the controls in the dynamic column you should use the ItemDataBound event, not the ItemCreated one.

Hope it helps.

Best wishes,
Tsvetoslav
the Telerik team

[NLV]

Oh yeah. Since the control creation is based on 'data' you need to use ItemDataBound.

[gmendez]

Thank you very much guys, for your valuable help.
I will try the proposed approch and let you know ASAP.
Best wishes,

Gonzalo

[gmendez]

Guys, you rock!

[gmendez]

Hello Again,
I followed your advice and it worked ok when displaying the grid and for letting the user entering values.
However, at a later stage I need to grab those values and then I run into trouble because the panel's controls collection contains only a literal control. I don't know why it doesn't preserve the original objects.
I created the template like this:

<telerik:GridTemplateColumn HeaderText="Indice el valor" UniqueName="ValorComparacion">
   <ItemTemplate>
       <asp:Panel ID="TemplatePanel" runat="server">

       </asp:Panel>
   </ItemTemplate>
</telerik:GridTemplateColumn>

Then, in the code behind I add the controls based on the databound data:

protected void GridFiltros_ItemDataBound(object sender, GridItemEventArgs e)
{
    if (e.Item.DataItem != null)
    {
        Panel p = (Panel)e.Item.FindControl("TemplatePanel");
        if (p != null)
        {
            TableFieldInfo info = (TableFieldInfo)e.Item.DataItem;
            switch (info.Tipo)
            {
                case TiposDato.Fecha:
                    p.Controls.Add(new RadDatePicker());
                    break;
                case TiposDato.Logico:
                    p.Controls.Add(new CheckBox());
                    RadComboBox operador = (RadComboBox)e.Item.FindControl("RadComboBoxOperador");
                    if (operador != null)
                        operador.Enabled = false;
                    break;
                default:
                    p.Controls.Add(new RadTextBox());
                    break;
            }
        }
    }
}

After that when the user clicks on a button I iterate over the rows.  I grab the panel from the row like this and call the method intended to read the control's value:

...
Panel p = (Panel)row["ValorComparacion"].FindControl("TemplatePanel");
string value = GetEditorValue(p, tipo);
...

Here's the GetEditorValue method definition:

private string GetEditorValue(Panel panel, string tipo)
{
    TiposDato tipoDato = (TiposDato)Enum.Parse(typeof(TiposDato), tipo);
    object valor;
    switch (tipoDato)
    {
        case TiposDato.Fecha:
            RadDatePicker dp = (RadDatePicker)panel.Controls[0];
            valor = dp.SelectedDate;
            break;
        case TiposDato.Logico:
            CheckBox ch = (CheckBox)panel.Controls[0];
            valor = ch.Checked;
            break;
        default:
            RadTextBox tb = (RadTextBox)panel.Controls[0];
            valor = tb.Text;
            break;
    }
    return valor.ToString();
}

And then, when the method tryes to cast the unique control the panel contains, it throws an exception because it's a literal control instead off a RadTextBox for example.
Any clue??
Thanks in advance,

Gonzalo

[gmendez]

Ok, I finally got it to work.
Instead of adding controls at runtime I created a user control containing all the different editors I need. I made all of them invisible.
Then, instead of adding a panel to the template as originally suggested I added my user control.
At runtime, using the ItemDatabound event I call a method on my user control (DynamicInput) in which I decide which editor to make visible depending on data from other columns.

...
DynamicInput di = (DynamicInput)e.Item.FindControl("DynamicInput1");
TableFieldInfo info = (TableFieldInfo)e.Item.DataItem;
di.DisplayEditor(info.Tipo);
...

Here's the code for the DisplayMethod:

public void DisplayEditor(TiposDato tipo)
{
    switch (tipo)
    {
        case TiposDato.Logico:
            this.CheckBox1.Visible=true;
            break;
        case TiposDato.Fecha:
            this.RadDatePicker1.Visible = true;
            this.RadDatePicker1.SelectedDate = DateTime.Today;
            this.RadDatePicker1.DateInput.CausesValidation = true;
            break;
        default:
             this.RadTextBox1.Visible=true;
             break;
    }
}

then, I iterarate over the rows and read the values like this:

foreach (GridDataItem row in this.GridFiltros.MasterTableView.Items)
{
    ...
    string tipo = row["Tipo"].Text;
    DynamicInput p = (DynamicInput)row["ValorComparacion"].FindControl("DynamicInput1");
    string value;
    value = p.GetValue((TiposDato)Enum.Parse(typeof(TiposDato), tipo));
    ...
}

And finally, the code for the GetValue method:

public string GetValue(TiposDato tipo)
{
    object valor="";
    switch (tipo)
    {
        case TiposDato.Logico:
            valor = this.CheckBox1.Checked;
            break;
        case TiposDato.Fecha:
            valor = this.RadDatePicker1.SelectedDate;
            break;
        default:
            valor = this.RadTextBox1.Text;
            break;
    }
    return valor.ToString();
}

This is working Ok for me.
Thanks a lot.

Regards,

Gonzalo

[Harry]

How do you handle postbacks from the controls created.  The conrols disappear  on postback.

[Harry]

Seems like a tacky solution.

[gmendez]

Hello Harry,

Sorry I can't help you. I don't even have access to the source code anymore.
Regards,

Gonzalo