How to Create a DropDownList in DataGrid

How to place a control in DataGrid

1. Place DataGrid
2. rightclick select "Propery Builder"
3. select "Columns" from lift panel
4. select "Temlate Column" in "Available Columns"
5. click on ">" (so that "Template Column" Appear in "Selected Column")
6. change the "Header Text", "Footer Text" etc.. as your wish
7. Click "OK"
8. rightClick on the grid and select "Edit Template" ---> "Columns[0]" (you have to select the column where you want to place the control)
9. place the control in one of the section
a. Item Template or
b. EditItem Template etc.. according to your requirement

Note: in our sample i place a dropdowlist in Item Template

Placeing a control in a DataGrid is very simple. If you place a Check box or Radio button and handling this control is very easy even DropDownList also. but when we face the dificulty? if you place a control (like check box, raido button, or DropDownList) then want to hanlding the control's event it give some difficulty. how to overcome this?

How to Handle the Event of that Control


To handle the event of that control, you have to write a procedure which going to fire when the event is fire. in our sample the procedure is "ddlGroup_SelectedIndexChanged"

In our sample code i have table called "DDLSample" and i have some datas, the script to generate the table and insert the data is


create table DDLSample (GroupName varchar(15), Items varchar(15))

insert into DDLSample values ('Fruit', 'Mango')
insert into DDLSample values ('Fruit', 'Orange')
insert into DDLSample values ('Fruit', 'Grape')

insert into DDLSample values ('Color', 'Red')
insert into DDLSample values ('Color', 'Green')
insert into DDLSample values ('Color', 'Blue')
insert into DDLSample values ('Color', 'Yellow')

insert into DDLSample values ('Animal', 'Dog')
insert into DDLSample values ('Animal', 'Cat')
insert into DDLSample values ('Animal', 'Lion')


open a vb.net or C#.Net ASP.Net web Application

place a Grid and AutoGenerateColumns to false

place two DropDownList in two columns and set the column Heading as "Group" and "Item" repectively

change dropdownlist's ID to "ddlGroup" and "ddlItem" respectively

in webform1's HTML editor in ddlGroup's propertiy add the following line
OnSelectedIndexChanged="ddlGroup_SelectedIndexChanged"

so that the ddlGroup's code should be like



AutoPostBack="True">


VB.Net


Imports System.Data.SqlClient



Declare the vriables as


Dim sqlConnection As sqlConnection
Dim sqlCommand As sqlCommand
Dim dsGroup As DataSet = New DataSet
Dim dsItem As DataSet = New DataSet
Dim daGroup As SqlDataAdapter
Dim daItem As SqlDataAdapter = New SqlDataAdapter



in page load



If Not IsPostBack Then
sqlConnection = New SqlConnection("initial catalog=[DBName];user id=sa;password=;server=(local)")
sqlConnection.Open()
sqlCommand = New SqlCommand("select distinct GroupName from ddlsample", sqlConnection)
sqlCommand.CommandType = CommandType.Text
daGroup = New SqlDataAdapter(sqlCommand)
daGroup.Fill(dsGroup, "dtGroup")
DataGrid1.DataSource = dsGroup
DataGrid1.DataBind()
End If



In DataGrid1_ItemDataBound


Dim dr As DataRowView = CType(e.Item.DataItem, DataRowView)
If ((e.Item.ItemType = ListItemType.Item) _
OrElse (e.Item.ItemType = ListItemType.AlternatingItem)) Then
Dim listGroup As DropDownList = CType(e.Item.FindControl("ddlGroup"), DropDownList)
listGroup.DataSource = dsGroup
listGroup.DataValueField = "GroupName"
listGroup.DataTextField = "GroupName"
listGroup.DataBind()
listGroup.Items.Insert(0, New ListItem("Select One", "Select One"))
End If


Our Own Procedure to fire the event


Protected Sub ddlGroup_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
Dim ddllist As DropDownList = CType(sender, DropDownList)
Dim cell As TableCell = CType(ddllist.Parent, TableCell)
Dim item As DataGridItem = CType(cell.Parent, DataGridItem)
Dim content As String = item.Cells(0).Text
Dim ddlType As DropDownList = CType(item.Cells(0).FindControl("ddlGroup"), DropDownList)
sqlConnection = New SqlConnection("initial catalog=SathyaSample;user id=sa;password=sa;server=(local)")
sqlConnection.Open()
sqlCommand = New SqlCommand(("select Items from ddlsample where GroupName = '" _
+ (ddlType.SelectedItem.Text + "'")), sqlConnection)
sqlCommand.CommandType = CommandType.Text
daItem = New SqlDataAdapter(sqlCommand)
daItem.Fill(dsItem, "dtItem")
Dim ddlItem As DropDownList = CType(item.Cells(1).FindControl("ddlItem"), DropDownList)
If (ddlType.SelectedItem.Text = "Select One") Then
ddlItem.Items.Clear()
Else
ddlItem.Items.Clear()
ddlItem.DataSource = dsItem
ddlItem.DataValueField = "Items"
ddlItem.DataTextField = "Items"
ddlItem.DataBind()
ddlItem.Items.Insert(0, New ListItem("Select One", "Select One"))
End If
End Sub

C#.Net


using System.Data.SqlClient;
Declare the vriables as
SqlConnection sqlConnection;
SqlCommand sqlCommand;
DataSet dsGroup=new DataSet();
DataSet dsItem=new DataSet();
SqlDataAdapter daGroup;
SqlDataAdapter daItem=new SqlDataAdapter();

in page load

if(!IsPostBack)
{
sqlConnection = new SqlConnection(@"initial catalog=SathyaSample;user id=sa;password=sa;server=(local)");
sqlConnection.Open();
sqlCommand = new SqlCommand("select distinct GroupName from ddlsample",sqlConnection);
sqlCommand.CommandType=CommandType.Text;
daGroup=new SqlDataAdapter(sqlCommand);
daGroup.Fill(dsGroup,"dtGroup");
DataGrid1.DataSource=dsGroup;
DataGrid1.DataBind();
}

In DataGrid1_ItemDataBound


DataRowView dr = (DataRowView) e.Item.DataItem;
if(e.Item.ItemType == ListItemType.Item || e.Item.ItemType==ListItemType.AlternatingItem)
{
DropDownList listGroup = (DropDownList)e.Item.FindControl("ddlGroup");
listGroup.DataSource = dsGroup;
listGroup.DataValueField = "GroupName";
listGroup.DataTextField = "GroupName";
listGroup.DataBind();
listGroup.Items.Insert(0,new ListItem("Select One","Select One"));
}



Our Own Procedure to fire the event


protected void ddlGroup_SelectedIndexChanged(object sender, EventArgs e)
{
DropDownList ddllist = (DropDownList)sender;
TableCell cell = ddllist.Parent as TableCell;
DataGridItem item = cell.Parent as DataGridItem;
string content = item.Cells[0].Text;
DropDownList ddlType=(DropDownList)item.Cells[0].FindControl("ddlGroup");
sqlConnection = new SqlConnection(@"initial catalog=SathyaSample;user id=sa;password=sa;server=(local)");
sqlConnection.Open();
sqlCommand = new SqlCommand("select Items from ddlsample where GroupName = '" + ddlType.SelectedItem.Text +"'",sqlConnection);
sqlCommand.CommandType=CommandType.Text;
daItem=new SqlDataAdapter(sqlCommand);
daItem.Fill(dsItem,"dtItem");
DropDownList ddlItem=(DropDownList)item.Cells[1].FindControl("ddlItem");
if (ddlType.SelectedItem.Text=="Select One")
{
ddlItem.Items.Clear();
}
else
{
ddlItem.Items.Clear();
ddlItem.DataSource=dsItem;
ddlItem.DataValueField="Items";
ddlItem.DataTextField="Items";
ddlItem.DataBind();
ddlItem.Items.Insert(0,new ListItem("Select One","Select One"));
}
}