how can i make this code more optimized

Question

how can i optimized this code? i dont like to have case statement, is there a way i can improve this code?

protected void ddlFilterResultBy_SelectedIndexChanged(object sender, EventArgs e)
{ 
    string selVal = ddlFilterResultBy.SelectedValue.ToString().ToLower();

    switch (selVal)
    {
        case "date":
            pnlDate.Visible = true; 
            pnlSubject.Visible = false;
            pnlofficer.Visible = false;
            pnlCIA.Visible = false;
            pnlMedia.Visible = false;
            pnlStatus.Visible = false;                    
            break;

        case "subject":
            pnlDate.Visible = false;
            pnlSubject.Visible = true;
            pnlofficer.Visible = false;
            pnlCIA.Visible = false;
            pnlMedia.Visible = false;
            pnlStatus.Visible = false;
            break;

        case "officer":
            pnlDate.Visible = false;
            pnlSubject.Visible = false;
            pnlofficer.Visible = true;
            pnlCIA.Visible = false;
            pnlMedia.Visible = false;
            pnlStatus.Visible = false;
            break;

        case "status":
            pnlDate.Visible = false;
            pnlSubject.Visible = false;
            pnlofficer.Visible = false;
            pnlCIA.Visible = false;
            pnlMedia.Visible = false;
            pnlStatus.Visible = true;
            break;

        default:
            pnlDate.Visible = false;
            pnlSubject.Visible = false;
            pnlofficer.Visible = false;
            pnlCIA.Visible = false;
            pnlMedia.Visible = false;
            pnlStatus.Visible = false;
            break;
    }
}

Answer 1

Easy enough. You're only ever making one item visible depending on the case option, so just set the visibility as follows:

pnlDate.Visible = (selVal == "date"); 
pnlSubject.Visible = (selVal == "subject");
pnlofficer.Visible = (selVal == "officer");
pnlCIA.Visible = false;
pnlMedia.Visible = false;
pnlStatus.Visible = (selVal == "status");    

This is better than setting everything to visible = false; and then only showing the item you need as this contains it all into just 6 lines of code for the actual visibility setting.

Answer 2

Another way:

// set everything to false   
Dictionary<string, type> d = new Dictionary<string, type>()
{
    {"date", pnlDate},
    {"subject", plnSubject},
    {"officer", plnOfficer},
    {"status", plnStatus}
};

d[selVal].Visible = true;

Answer 3

protected void ddlFilterResultBy_SelectedIndexChanged(object sender, EventArgs e)
            { 
                string selVal = ddlFilterResultBy.SelectedValue.ToString().ToLower();
                        pnlDate.Visible = false;
                        pnlSubject.Visible = false;
                        pnlofficer.Visible = false;
                        pnlCIA.Visible = false;
                        pnlMedia.Visible = false;
                        pnlStatus.Visible = false;
                switch (selVal)
                {
                    case "date":
                        pnlDate.Visible = true;                    
                        break;

                    case "subject":
                        pnlSubject.Visible = true;
                        break;

                    case "officer":
                        pnlofficer.Visible = true;
                        break; 
                    case "status":
                        pnlStatus.Visible = true;
                        break;  
                }

            }