Populate (Bind) Month based on Year selection in ASP.Net GridView row using C# and VB.Net

Hi namojainashish,

Refer below code.

HTML

<form id="form1" runat="server">
    <asp:ScriptManager runat="server" />
    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" OnRowDataBound="GridView1_RowDataBound">
        <Columns>
            <asp:BoundField DataField="Year" HeaderText="Year" />
            <asp:TemplateField HeaderText="YearMonth">
                <ItemTemplate>
                    <asp:UpdatePanel runat="server">
                        <ContentTemplate>
                            <asp:DropDownList runat="server" ID="ddly" AutoPostBack="true" OnSelectedIndexChanged="ddly_SelectedIndexChanged">
                            </asp:DropDownList>
                            <asp:DropDownList runat="server" ID="ddlm">
                            </asp:DropDownList>
                        </ContentTemplate>
                    </asp:UpdatePanel>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>
</form>

Namespaces

 C#

using System.Data;
using System.Globalization;

VB.Net

Imports System.Data
Imports System.Globalization

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[] { new DataColumn("Id"), new DataColumn("Year") });
        dt.Rows.Add(1, "2015");
        dt.Rows.Add(2, "2017");
        dt.Rows.Add(3, "2020");
        dt.Rows.Add(4, "2021");
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
}

private void BindMonthandYearsInDropDown(DropDownList ddly, DropDownList ddlm, int year)
{
    DateTimeFormatInfo info = DateTimeFormatInfo.GetInstance(null);

    ddly.Items.Clear();
    int CurrentYear = DateTime.Today.Year;
    for (int i = 2015; i <= CurrentYear; i++)
    {
        ddly.Items.Add(i.ToString());
    }

    ddlm.Items.Clear();
    ddly.SelectedIndex = ddly.Items.IndexOf(ddly.Items.FindByText(year.ToString()));
    if (Convert.ToString(DateTime.Now.Year) == year.ToString())
    {
        for (int i = 1; i <= DateTime.Today.Month; i++)
        {
            ddlm.Items.Add(new System.Web.UI.WebControls.ListItem(info.GetMonthName(i), i.ToString()));
        }
    }
    else
    {
        for (int i = 1; i < 13; i++)
        {
            ddlm.Items.Add(new System.Web.UI.WebControls.ListItem(info.GetMonthName(i), i.ToString()));
        }
    }

}
protected void ddly_SelectedIndexChanged(object sender, EventArgs e)
{
    DropDownList ddly = sender as DropDownList;
    GridViewRow row = ddly.NamingContainer as GridViewRow;
    DropDownList ddlm = row.FindControl("ddlm") as DropDownList;
    int year = Convert.ToInt32(ddly.SelectedValue);
    BindMonthandYearsInDropDown(ddly, ddlm, year);
}

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DropDownList ddly = e.Row.FindControl("ddly") as DropDownList;
        DropDownList ddlm = e.Row.FindControl("ddlm") as DropDownList;
        int year = Convert.ToInt32(e.Row.Cells[0].Text.Trim());
        BindMonthandYearsInDropDown(ddly, ddlm, year);
    }
}

VB.Net

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
        If Not Me.IsPostBack Then
            Dim dt As DataTable = New DataTable()
            dt.Columns.AddRange(New DataColumn() {New DataColumn("Id"), New DataColumn("Year")})
            dt.Rows.Add(1, "2015")
            dt.Rows.Add(2, "2017")
            dt.Rows.Add(3, "2020")
            dt.Rows.Add(4, "2021")
            GridView1.DataSource = dt
            GridView1.DataBind()
        End If
    End Sub

    Private Sub BindMonthandYearsInDropDown(ByVal ddly As DropDownList, ByVal ddlm As DropDownList, ByVal year As Integer)
        Dim info As DateTimeFormatInfo = DateTimeFormatInfo.GetInstance(Nothing)
        ddly.Items.Clear()
        Dim CurrentYear As Integer = DateTime.Today.Year

        For i As Integer = 2015 To CurrentYear
            ddly.Items.Add(i.ToString())
        Next

        ddlm.Items.Clear()
        ddly.SelectedIndex = ddly.Items.IndexOf(ddly.Items.FindByText(year.ToString()))

        If Convert.ToString(DateTime.Now.Year) = year.ToString() Then

            For i As Integer = 1 To DateTime.Today.Month
                ddlm.Items.Add(New System.Web.UI.WebControls.ListItem(info.GetMonthName(i), i.ToString()))
            Next
        Else

            For i As Integer = 1 To 13 - 1
                ddlm.Items.Add(New System.Web.UI.WebControls.ListItem(info.GetMonthName(i), i.ToString()))
            Next
        End If
    End Sub

    Protected Sub ddly_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
        Dim ddly As DropDownList = TryCast(sender, DropDownList)
        Dim row As GridViewRow = TryCast(ddly.NamingContainer, GridViewRow)
        Dim ddlm As DropDownList = TryCast(row.FindControl("ddlm"), DropDownList)
        Dim year As Integer = Convert.ToInt32(ddly.SelectedValue)
        BindMonthandYearsInDropDown(ddly, ddlm, year)
    End Sub

    Protected Sub GridView1_RowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
        If e.Row.RowType = DataControlRowType.DataRow Then
            Dim ddly As DropDownList = TryCast(e.Row.FindControl("ddly"), DropDownList)
            Dim ddlm As DropDownList = TryCast(e.Row.FindControl("ddlm"), DropDownList)
            Dim year As Integer = Convert.ToInt32(e.Row.Cells(0).Text.Trim())
            BindMonthandYearsInDropDown(ddly, ddlm, year)
        End If
    End Sub

Screenshot