Avoid postback operation for asp dropdown onselected index

Question

I have two dropdownlists 'PakPeriod' and 'PackageName'  in update form, 'Pack period' binding in '.axpx' page only, but 'PackName' binding in 'PackPeriod_SelectedIndexChange' event from database.

 

problem: when I clicking 'packperiod' then page getting post back, I have to avoid this post back and should work 'PackPeriod_SelectedIndexChange' (for bind 'PackageName' dropdown list and other jobs) and update form on 'update' button click,

I used update panel also but its  not working , so what is the solution ?

 

/*packPeriod Bind*/ 

 

<asp:dropdownlist ID="ddlPackPeriod" runat="server" AutoPostBack="True" >

<asp:ListItem Value="0">Select</asp:ListItem>

<asp:ListItem Value="Monthly">Monthly</asp:ListItem>

<asp:ListItem Value="Quarterly">Quarterly</asp:ListItem>

<asp:ListItem Value="HalfYearly">HalfYearly</asp:ListItem>

<asp:ListItem Value="Yearly">Yearly</asp:ListItem>

</asp:dropdownlist>

 

 

/*Pckname bindind*/ 

 

public void ddlUpdatepackNameBind()

{

string period = ddlPackPeriodEdit.SelectedValue;

try

{

//open the db connection if it is closed...

if (connection.State == ConnectionState.Closed)

connection.Open();

string packagePeriod = ddlPackPeriodEdit.SelectedValue;

switch (period)

{

case "Monthly":

command = new SqlCommand();

command.CommandText = "sp_Get_PackName";

command.CommandType = CommandType.StoredProcedure;

command.Connection = connection;

command.Parameters.AddWithValue("@packagePeriod", packagePeriod);

ddlPackNameEdit.DataSource = command.ExecuteReader();

ddlPackNameEdit.DataTextField = "PackageName";

ddlPackNameEdit.DataValueField = "PackageId";

ddlPackNameEdit.DataBind();

ddlPackNameEdit.Items.Insert(0, new ListItem("--Select Package Name--", "0"));

break;

case "Quarterly":

command = new SqlCommand();

command.CommandText = "sp_Get_PackName";

command.CommandType = CommandType.StoredProcedure;

command.Connection = connection;

command.Parameters.AddWithValue("@packagePeriod", packagePeriod);

ddlPackNameEdit.DataSource = command.ExecuteReader();

ddlPackNameEdit.DataTextField = "PackageName";

ddlPackNameEdit.DataValueField = "PackageId";

ddlPackNameEdit.DataBind();

ddlPackNameEdit.Items.Insert(0, new ListItem("--Select Package Name--", "0"));

break;

case "HalfYearly":

command = new SqlCommand();

command.CommandText = "sp_Get_PackName";

command.CommandType = CommandType.StoredProcedure;

command.Connection = connection;

command.Parameters.AddWithValue("@packagePeriod", packagePeriod);

ddlPackNameEdit.DataSource = command.ExecuteReader();

ddlPackNameEdit.DataTextField = "PackageName";

ddlPackNameEdit.DataValueField = "PackageId";

ddlPackNameEdit.DataBind();

ddlPackNameEdit.Items.Insert(0, new ListItem("--Select Package Name--", "0"));

break;

case "Yearly":

command = new SqlCommand();

command.CommandText = "sp_Get_PackName";

command.CommandType = CommandType.StoredProcedure;

command.Connection = connection;

command.Parameters.AddWithValue("@packagePeriod", packagePeriod);

ddlPackNameEdit.DataSource = command.ExecuteReader();

ddlPackNameEdit.DataTextField = "PackageName";

ddlPackNameEdit.DataValueField = "PackageId";

ddlPackNameEdit.DataBind();

ddlPackNameEdit.Items.Insert(0, new ListItem("--Select Package Name--", "0"));

break;

}

}

catch (Exception ex)

{

Response.Write(ex.Message);

}

finally //Close db Connection if it is open....

{

if (connection.State == ConnectionState.Open)

connection.Close();

}

}

 

/*updating form*/ 

 

public void packUpdate()

{

try

{

//open the db connection if it is closed...

if (connection.State == ConnectionState.Closed)

connection.Open();

int packageId = Convert.ToInt32(ddlPackNameEdit.SelectedValue);

string packNewName = txtPackNameEdit.Text;

string packNewPeriod = ddlPackPeriodEdit.SelectedItem.ToString();

string packNewPrice = txtPackPriceEdit.Text;

command = new SqlCommand();

command.CommandText = "sp_PackageUpdate";

command.CommandType = CommandType.StoredProcedure;

command.Parameters.AddWithValue("@packageId", packageId);

command.Parameters.AddWithValue("@packNewName", packNewName);

command.Parameters.AddWithValue("@packNewPeriod", packNewPeriod);

command.Parameters.AddWithValue("@packNewPrice", packNewPrice);

command.Connection = connection;

command.ExecuteNonQuery();

lblMessage.Text = "Record Updated successfully";

lblMessage.Visible = true;

ddlPackNameEdit.SelectedIndex = -1;

ddlPackPeriodEdit.SelectedIndex = -1;

txtPackNameEdit.Text = "";

txtPackPriceEdit.Text = "";

}

catch (Exception ex)

{

Response.Write(ex.Message);

}

finally //Close db Connection if it is open....

{

if (connection.State == ConnectionState.Open)

connection.Close();

}

}

 

/*Update form*/ 

protected void btnPackageUpdate_Click(object sender, EventArgs e)

{

packUpdate();

}