Question

I’m new to c#, as in.

I’m currently working on a search function in c# using 3 DropDownLists and a submit button. When a user select an item on DropDownList and click submit, it will print the table for the respective selection.

There are 3 DropDownLists:

1. a province,
2. city,
3. specialization.

This will search the available doctors that suits the selection. For example I choose province1 on 1st DropDownList, city1 on the 2nd and a psychologist on 3rd, when the submit button is fired, it will print the available doctors that is in province1, city1 and has a specialization of psychologist.

I already have a code, still figuring it out but, when i click the submit button, nothing is happening. Can someone help me?

Here’s what I’ve done so far:

public partial class Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(1000);

        if (!IsPostBack)
        {
            string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
            SqlConnection conn = new SqlConnection(constring);
            DataTable dt = new DataTable("emed_province");

            using (conn)
            {
                conn.Open();
                SqlCommand comm = new SqlCommand("SELECT * FROM emed_province ORDER BY PROVINCE_NAME ASC", conn);
                SqlDataAdapter adptr = new SqlDataAdapter(comm);
                adptr.Fill(dt);
            }

            ddlProvince.DataSource = dt;
            ddlProvince.DataTextField = "PROVINCE_NAME";
            ddlProvince.DataValueField = "PROVINCE_CODE";
            ddlProvince.DataBind();

            ddlProvince.Items.Insert(0, new ListItem("---------------SELECT---------------", "0"));
            ddlCity.Items.Insert(0, new ListItem("---------------SELECT---------------", "0"));
            ddlSpec.Items.Insert(0, new ListItem("---------------SELECT---------------", "0"));
        }
    }

    protected void ddlProvince_SelectedIndexChanged(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(1000);

        string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
        SqlConnection conn = new SqlConnection(constring);
        DataTable dt = new DataTable("emed_province");

        using (conn)
        {
            conn.Open();
            SqlCommand comm = new SqlCommand("SELECT * FROM emed_city WHERE PROVINCE_CODE =@pcode", conn);
            comm.Parameters.AddWithValue("@pcode", ddlProvince.SelectedValue);
            SqlDataAdapter adptr = new SqlDataAdapter(comm);
            adptr.Fill(dt);

            SqlParameter param = new SqlParameter();
            param.ParameterName = "@pcode";
            param.Value = ddlProvince;

            comm.Parameters.Add(param);
        }
        ddlCity.DataSource = dt;
        ddlCity.DataTextField = "CITY_NAME";
        ddlCity.DataValueField = "CITY_CODE";
        ddlCity.DataBind();

        ddlCity.Items.Insert(0, new ListItem("---------------SELECT---------------", "0"));
    }

    protected void ddlCity_SelectedIndexChanged(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(1000);

        string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
        SqlConnection conn = new SqlConnection(constring);
        DataTable dt = new DataTable("emed_city");

        using (conn)
        {
            conn.Open();
            SqlCommand comm = new SqlCommand("SELECT * FROM emed_specialization", conn);
            comm.Parameters.AddWithValue("@ccode", ddlCity.SelectedValue);
            SqlDataAdapter adptr = new SqlDataAdapter(comm);
            adptr.Fill(dt);

            SqlParameter param = new SqlParameter();
            param.ParameterName = "@ccode";
            param.Value = ddlCity;

            comm.Parameters.Add(param);
        }
        ddlSpec.DataSource = dt;
        ddlSpec.DataTextField = "SPEC_NAME";
        ddlSpec.DataValueField = "SPEC_CODE";
        ddlSpec.DataBind();

        ddlSpec.Items.Insert(0, new ListItem("---------------SELECT---------------", "0"));
    }

    protected void btnSub_Click(object sender, EventArgs e)
    {
        string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
        SqlConnection conn = new SqlConnection(constring);
        DataTable dt = new DataTable("emed_doctors");
        using (conn)
        {
            conn.Open();
            SqlCommand comm = new SqlCommand("SELECT DOCTOR_NAME FROM emed_doctors where Province = '" + ddlProvince.SelectedItem.ToString() + "'", conn);
            SqlDataAdapter adptr = new SqlDataAdapter(comm);
            adptr.Fill(dt);
        }
    }
}

Answer 1

Make change in this line of code which is in submit button click function

Correct code:

SqlCommand comm = new SqlCommand("SELECT DOCTOR_NAME FROM emed_doctors where province = '" + ddlProvince.SelectedItem.ToString() + "'", conn); 

because as you see your code query is incorrent have look to your code which is incorrect

Wrong code:

SqlCommand comm = new SqlCommand("SELECT DOCTOR_NAME FROM emed_doctors where (" + ddlProvince.SelectedItem.ToString() + " ", conn); 

Edit:

if you want to display record that you got in DataTable you either need loop through the records or you need to use GridView for that…i think you miss that thing

in above one after where clause you miss the name of the filed you need to made filter on… i have written update code by modifying that condition.

See MSDN for GridView.