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Chris Maunder12-Jul-09 23:39
cofounderChris Maunder12-Jul-09 23:39 
Questionis it hard to add new module into Umbraco CMS? Pin
Southmountain7-Feb-24 9:23
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AnswerRe: is it hard to add new module into Umbraco CMS? Pin
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QuestionUI library for ASP.NET Core MVC Razor Pin
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QuestionCoding Help Pin
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AnswerRe: Coding Help Pin
Richard MacCutchan24-Nov-23 23:05
mveRichard MacCutchan24-Nov-23 23:05 
AnswerRe: Coding Help Pin
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AnswerRe: Coding Help Pin
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QuestionWhat should I start reading to get to where I want to go? Pin
DalTXColtsFan21-Nov-23 12:46
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AnswerRe: What should I start reading to get to where I want to go? Pin
Richard MacCutchan21-Nov-23 22:37
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QuestionSelectedIndexChanged for DropDown not fired when first item selected Pin
DalTXColtsFan17-Nov-23 8:41
DalTXColtsFan17-Nov-23 8:41 
AnswerRe: SelectedIndexChanged for DropDown not fired when first item selected Pin
Ron Nicholson17-Nov-23 8:57
professionalRon Nicholson17-Nov-23 8:57 
GeneralRe: SelectedIndexChanged for DropDown not fired when first item selected Pin
DalTXColtsFan17-Nov-23 9:03
DalTXColtsFan17-Nov-23 9:03 
GeneralRe: SelectedIndexChanged for DropDown not fired when first item selected Pin
Andre Oosthuizen18-Nov-23 8:27
mveAndre Oosthuizen18-Nov-23 8:27 
Ron is absolutely correct, When the page is loaded for the first time, the 'Page_Load' event is triggered, and the 'ddlCategory_SelectedIndexChanged' event is not fired because the 'AutoPostBack' property is set to True. However, when you select the first item in the dropdown, the page is posted back to the server, and the 'Page_Load' event is triggered again. This causes the selected index to be reset, and the 'ddlCategory_SelectedIndexChanged' event is not fired.

You should only populate the dropdown list during the initial page load and not on subsequent 'postbacks'. You can do this by wrapping your code inside the 'Page_Load' event with a check for '!IsPostBack' -

C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        Label3.Text = "In Page Load selected index is " + ddlCategory.SelectedIndex.ToString();
        XXXDbSupport objDBSupport = new XXXDbSupport();
        DbCommand objDBCommand = objDBSupport.CreateDbCommand();
        objDBCommand.CommandType = CommandType.Text;
        string sSQL = "select distinct isnull(Category,'(blank)') as ProdCat from xxx_product order by isnull(Category,'(blank)')";
        objDBCommand.CommandText = sSQL;
        DataTable objDBTable = objDBSupport.FillDataTable(objDBCommand);
        if (objDBTable.Rows.Count > 0)
        {
            ddlCategory.DataTextField = "ProdCat";
            ddlCategory.DataValueField = "ProdCat";
            ddlCategory.DataSource = objDBTable;
            ddlCategory.DataBind();
        }
        else
        {
            ddlCategory.Text = "n/a";
        }
    }
}

protected void ddlCategory_SelectedIndexChanged(object sender, EventArgs e)
{
    Label2.Text = "The selected index changed to " + ddlCategory.SelectedIndex.ToString();
    XXXDbSupport objDBSupport = new XXXDbSupport();
    DbCommand objDBCommand = objDBSupport.CreateDbCommand();
    objDBCommand.CommandType = CommandType.Text;
    string sSQL = "select distinct isnull(SubCategory,'(blank)') as SubCat from xxx_product ";
    if (ddlCategory.Text == "(blank)")
    {
        sSQL = sSQL + "where isnull(Category,'(blank)') = '(blank)' order by isnull(SubCategory,'(blank)')";
    }
    else
    {
        sSQL = sSQL + "where Category = '" + ddlCategory.Text + "' order by isnull(SubCategory,'(blank)')";
    }
    objDBCommand.CommandText = sSQL;
    DataTable objDBTable = objDBSupport.FillDataTable(objDBCommand);
    if (objDBTable.Rows.Count > 0)
    {
        ddlSubcategory.DataTextField = "SubCat";
        ddlSubcategory.DataValueField = "SubCat";
        ddlSubcategory.DataSource = objDBTable;
        ddlSubcategory.DataBind();
    }
    else
    {
        ddlSubcategory.Text = "n/a";
    }
}

SuggestionRe: SelectedIndexChanged for DropDown not fired when first item selected Pin
Richard Deeming19-Nov-23 22:56
mveRichard Deeming19-Nov-23 22:56 
QuestionDumb it down for one who's basically a beginner Pin
DalTXColtsFan15-Nov-23 6:31
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AnswerRe: Dumb it down for one who's basically a beginner Pin
Andre Oosthuizen15-Nov-23 8:25
mveAndre Oosthuizen15-Nov-23 8:25 
GeneralRe: Dumb it down for one who's basically a beginner Pin
DalTXColtsFan15-Nov-23 12:48
DalTXColtsFan15-Nov-23 12:48 
GeneralRe: Dumb it down for one who's basically a beginner Pin
Andre Oosthuizen16-Nov-23 6:36
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Questioncan't build blazor library in azure pipeline Pin
Super Lloyd6-Sep-23 18:08
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AnswerRe: can't build blazor library in azure pipeline Pin
Super Lloyd6-Sep-23 19:27
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QuestionBlazor component debugging Pin
Super Lloyd23-Aug-23 15:16
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AnswerRe: Blazor component debugging Pin
Super Lloyd24-Aug-23 18:27
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QuestionHTML SELECT CONTROL WITH RUNAT="SERVER Pin
tchia_k30-Jul-23 4:53
professionaltchia_k30-Jul-23 4:53 
AnswerRe: HTML SELECT CONTROL WITH RUNAT="SERVER Pin
Richard Deeming30-Jul-23 23:14
mveRichard Deeming30-Jul-23 23:14 

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