Bind data to dropdownlist and selectedvalue by C#

Linh Hoai

I have two table:

Category : CatID, CatName

News : NewsID, CatID,Title,Content

Now, i want, when i edit on table NewS, i have dropdownlist and bind all values from table Category and show SelectedValue previous

Please help me

6 Replies

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Linh Hoai7y ago
Hi Ramas!

It's OKIE.
Thank you very much
Rafnas T P7y ago
hi,

selected value give category Id from News Table
try changing code as shown below
try
{
SqlConnection conn = new SqlConnection(connStr);
SqlDataReader reader = null;
conn.Open();
string sql = "SELECT * FROM NEWS where NewsID= " + sid + "";
SqlCommand comm = new SqlCommand();
comm.Connection = conn;
comm.CommandText = sql;
reader = comm.ExecuteReader();
while (reader.Read())
{
string Newsid = reader.GetValue(reader.GetOrdinal("Newsid")).ToString();
string CatID = reader.GetValue(reader.GetOrdinal("CatID")).ToString();
string Title = reader.GetValue(reader.GetOrdinal("Title")).ToString();
string Content = reader.GetValue(reader.GetOrdinal("Content")).ToString();
if (Newsid != "")
{
SqlDataReader reader = null;
string sql = "SELECT CatID, CatName FROM Category order by Catid desc";
SqlCommand comm = new SqlCommand();
comm.Connection = conn;
comm.CommandText = sql;
reader = comm.ExecuteReader();
while (reader.Read())
{
Dropdownlist.DataSource = reader;
Dropdownlist.DataValueField = "CatID";
Dropdownlist.DataTextField = "CatName";
Dropdownlist.DataBind();
}
Dropdownlist.SelectedValue = CatID ;
}
}
Linh Hoai7y ago
Hi Jangid!

I try your code , but when i show my form, dropdownlist not show value " selected" (Which value of CATID in table NEWS)
Gajendra Jangid7y ago
1. TRY THIS CODE
3. String str = "cONN STRING HERE";
4. SqlConnection con = new SqlConnection(str);
5. SqlCommand cmd = new SqlCommand("SELECT * FROM NEWS where NewsID = '" + DropDownList1.SelectedValue + "'", con);
6. SqlDataAdapter Adpt = new SqlDataAdapter(cmd);
7. DataTable dt = new DataTable();
8. Adpt.Fill(dt);
9. if (dt.Rows.Count > 0)
10. {
11. string Newsid = dt.Rows[0]["Newsid"].ToString();
12. string CatID = dt.Rows[0]["CatID"].ToString();
13. string Title = dt.Rows[0]["Title"].ToString();
14. string Content = dt.Rows[0]["Content"].ToString();
16. if (Newsid != "")
17. {
18. string sql = "SELECT CatID, CatName FROM Category order by Catid desc";
19. SqlCommand cmd1 = new SqlCommand(sql , con);
20. SqlDataAdapter Adpt1 = new SqlDataAdapter(cmd1);
21. DataTable dt1 = new DataTable();
22. Adpt1.Fill(dt1);
23. if (dt1.Rows.Count > 0)
24. {
25. string CatID_root = dt.Rows[0]["CatID"].ToString();
26. string CatName = dt.Rows[0]["CatName"].ToString();
27. if (CatID_root == CatID)
28. {
29. Dropdownlist.selectedvalue= CatId;
30. }
31. else
32. {
33. Dropdownlist.DataSource = dt1;
34. Dropdownlist.DataValueField = "CatID";
35. Dropdownlist.DataTextField = "CatName";
36. Dropdownlist.DataBind();
37. }
38. }
39. }
40. }

Linh Hoai7y ago

Hi Jangid

Here my code , but it fail :

try
{
SqlConnection conn = new SqlConnection(connStr);
SqlDataReader reader = null;
conn.Open();
string sql = "SELECT * FROM NEWS where NewsID= " + sid + "";
SqlCommand comm = new SqlCommand();
comm.Connection = conn;
comm.CommandText = sql;
reader = comm.ExecuteReader();
while (reader.Read())
{
string Newsid = reader.GetValue(reader.GetOrdinal("Newsid")).ToString();
string CatID = reader.GetValue(reader.GetOrdinal("CatID")).ToString();
string Title = reader.GetValue(reader.GetOrdinal("Title")).ToString();
string Content = reader.GetValue(reader.GetOrdinal("Content")).ToString();
if (Newsid != "")
{
SqlDataReader reader = null;
string sql = "SELECT CatID, CatName FROM Category order by Catid desc";
SqlCommand comm = new SqlCommand();
comm.Connection = conn;
comm.CommandText = sql;
reader = comm.ExecuteReader();
while (reader.Read())
{
string CatID_root = reader.GetValue(reader.GetOrdinal("CatID")).ToString();
string CatName = reader.GetValue(reader.GetOrdinal("CatName")).ToString();
if (CatID_root == CatID)
{
Dropdownlist.DataSource = reader;
Dropdownlist.DataValueField = "CatID";
Dropdownlist.DataTextField = "CatName";
Dropdownlist.SelectedValue = CatName;
Dropdownlist.DataBind();
}
else
{
Dropdownlist.DataSource = reader;
Dropdownlist.DataValueField = "CatID";
Dropdownlist.DataTextField = "CatName";
Dropdownlist.DataBind();
}
}
}
}

Gajendra Jangid7y ago

Hii Linh

Use like as below:

call this function on dropdown change event

protected void ddl_selectdvaluechange(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(str);
SqlCommand cmd = new SqlCommand("select * from UserDetail where id = '" + DropDownList1.SelectedValue + "'", con);
SqlDataAdapter Adpt = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
Adpt.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();
}

or you can use following links:

https://www.c-sharpcorner.com/UploadFile/rohatash/binding-dropdownlist-with-database-and-display-data-in-gridv/

https://www.telerik.com/forums/bind-selectedvalue-after-populating-dropdownlist

https://www.aspsnippets.com/Articles/Populate-DropDownList-with-Selected-Value-in-EditItemTemplate-of-GridView-in-ASPNet.aspx