Change gridview header text when i choose dropdownlist
<p>I have some doubt
This is my coding for aspx page and .cs page
How can I achieve the following 
If i select February the header text assigned January value and i select march then assign February value...Could you please help me find a solution for it</p>

<pre><code>&lt;asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"
onselectedindexchanged="DropDownList1_SelectedIndexChanged"&gt;
&lt;/asp:DropDownList&gt;

&lt;asp:GridView ID="GridView1" runat="server" &gt;
&lt;Columns&gt;
&lt;asp:TemplateField HeaderText="8-14"&gt;
&lt;ItemTemplate&gt;
&lt;asp:TextBox ID="TxtWeek2" runat="server"&gt;&lt;/asp:TextBox&gt;
&lt;/ItemTemplate&gt;
&lt;/asp:TemplateField&gt;
&lt;/Columns&gt;
&lt;/asp:GridView&gt;
</code></pre>

<p>In .CS page</p>

<pre><code>protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DropDownList1.Items.Add("Select");
DropDownList1.Items.Add("January");
DropDownList1.Items.Add("February");
DropDownList1.Items.Add("March");
DropDownList1.Items.Add("April");
DropDownList1.Items.Add("May");

SqlConnection cn = new SqlConnection("Data Source=192.169.10.22;Initial Catalog=SHRICITYUNO;User ID=uno;Password=uno");
SqlCommand cmd = new SqlCommand();
cn.Open();
cmd = new SqlCommand("SELECT Week1 FROM Finman_FundPlan", cn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
GridView1.DataSource = ds;
GridView1.DataBind();
}

}


protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
string s = DropDownList1.SelectedItem.Text.ToString();
if (DropDownList1.SelectedItem.Text == "January")
{
this.GridView1.Columns[0].HeaderText = "";
this.GridView1.Columns[0].HeaderText = "29-31";
}
else if (DropDownList1.SelectedItem.Text == "February")
{
this.GridView1.Columns[0].HeaderText = "";
this.GridView1.Columns[0].HeaderText = "-";
}
else if (DropDownList1.SelectedItem.Text == "March")
{
this.GridView1.Columns[0].HeaderText = "";
this.GridView1.Columns[0].HeaderText = "29-31";
}
else if (DropDownList1.SelectedItem.Text == "April")
{
this.GridView1.Columns[0].HeaderText = "";
this.GridView1.Columns[0].HeaderText = "29-30";
}
else if (DropDownList1.SelectedItem.Text == "May")
{
this.GridView1.Columns[0].HeaderText = "";
this.GridView1.Columns[0].HeaderText = "29-31";
}
}
</code></pre>
