CODEWITHSUNDEEP
c#sqlasp.net
sudipchand7139
sudipchand7139

Reputation: 55

Data not shown in DropDownList from database

I have two tables; they are tblcity and tblarea in database like:

tblcity

city id | city
--------------
1       | ktm
2       | bkt
3       | lat

tblcity

areaid | cityid | area
----------------------
1      |    1   |  a
2      |    1   |  b
3      |    1   |  c
4      |    2   |  d
5      |    2   |  e
6      |    3   |  f
7      |    3   |  g

The city table consists of three city name i.e ktm, bkt, lat. Whereas table area consists the name of area in that city.

I have shown all the city name in one dropdownlist i.e DropDownList1. Now I am trying to do is to show all the respective area name of that city in another dropdownlist i.e in DropDownList7 when i select one of the city name in DropDownList1.

Like if select city ktm in DropDownList1 only area name like a, b, c of city ktm should be should be shown in DropDownList7.

Now the problem is that, here I am able to show all the city name in DropDownList1 but on selecting one of the city in DropDownList1 the area name belonging to that city are not shown in DropDownList7.

 <asp:DropDownList ID="DropDownList1" CssClass="form-control shadow2 input-lg" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
                        </asp:DropDownList>
                        <asp:DropDownList ID="DropDownList7" runat="server" Height="111px" Width="376px"></asp:DropDownList>

Code behind

 protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {

        DataTable dt = c.getallcity();
        if (dt.Rows.Count>0)
        {
            DataRow dr = dt.NewRow();
            dr["city"] = "select city ";
            dt.Rows.InsertAt(dr, 0);
            DropDownList1.DataSource = dt;
            DropDownList1.DataTextField = "city";
            DropDownList1.DataValueField = "cityid";
            DropDownList1.DataBind();


        }


    }
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (DropDownList1.SelectedIndex!= 0)
    {
        DataTable dt = c.getareabycityid(Convert.ToInt32(DropDownList1.SelectedValue.ToString()));
        if (dt.Rows.Count>0)
        {
            DataRow dr = dt.NewRow();
            dr["area"] = "select area ";
            dt.Rows.InsertAt(dr, 0);
            DropDownList7.DataSource = dt;
            DropDownList7.DataTextField = "area";
            DropDownList7.DataValueField = "areaid";
            DropDownList7.DataBind();

        }

    }

}

Method used

public DataTable getallcity()
{
    SqlConnection con = new SqlConnection(WebConfigurationManager.ConnectionStrings["myconnection"].ConnectionString);
    string sql = "select * from tblcity";
    SqlCommand cmd = new SqlCommand(sql, con);

    SqlDataAdapter da = new SqlDataAdapter(cmd);

    //---datasource---da----datatable,dataset

    DataTable dt = new DataTable();
    da.Fill(dt);

    return dt;
}
public DataTable getareabycityid(int cityid)
{
    SqlConnection con = new SqlConnection(WebConfigurationManager.ConnectionStrings["myconnection"].ConnectionString);
    string sql = "select * from tblarea where cityid=@cityid";
    SqlCommand cmd = new SqlCommand(sql, con);
    cmd.Parameters.AddWithValue("@cityid", cityid);
    SqlDataAdapter da = new SqlDataAdapter(cmd);

    //---datasource---da----datatable,dataset

    DataTable dt = new DataTable();
    da.Fill(dt);

    return dt;
}

Upvotes: 0

Views: 61

Answers (2)

Antoine Pelletier
Antoine Pelletier

Reputation: 3326

First of all, your <asp:DropDownList ID="DropDownList1"> should contains Autopostback property like this :

<asp:DropDownList id="ddlId" runat="server" AutoPostBack="True"/>

then i would put a break point just before

if (dt.Rows.Count>0)
{
}

and check what this DataTable dt contains

Upvotes: 1

Rahul
Rahul

Reputation: 77934

You need to set the property AutoPostBack = true for your dropdown list DropDownList1

Upvotes: 0

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