Fetch (Get) DateTime from TextBox and insert in database using C# in ASP.Net

I am using Azure database. 

Datatype in table is Datetime.

I need to get date selection from user Textbox and insert data in table at button click.

How to do.

I am getting Object reference not set to an instance of an object.System.NullReferenceException: Object reference not set to an instance of an object. at HRData.Mufins.pgMufinAdmin.btnSubmit_Click(Object sender, EventArgs e) in D:\Development_Web\7 February 2020\11022020 HRData Mufins\HRData\Mufins\pgMufinAdmin.aspx.cs:line 70

        protected void btnSubmit_Click(object sender, EventArgs e)
        {
            try
            {
                startDate= DateTime.ParseExact(txtEDate.Text, "MM-dd-yyyy", CultureInfo.InvariantCulture);
                SqlCommand cmd1 = new SqlCommand("Insert into tblMusterAdmin values(@Date,@LocCode,@empid,@request,@Status)", con);
                cmd1.Parameters.AddWithValue("@Date",startDate);
                cmd1.Parameters.AddWithValue("@LocCode",ddlBranch.SelectedValue);
                cmd1.Parameters.AddWithValue("@empid",ddlEmp.SelectedValue);
                cmd1.Parameters.AddWithValue("@request",Convert.ToInt32(Session["userid"].ToString()));
                cmd1.Parameters.AddWithValue("@Status",'A');
                con.Open();
                int a=cmd1.ExecuteNonQuery();
                if (a > 0)
                {
                    lblMessage.Text = "Admin ID: " + ddlEmp.Text + "Mapped Successfully for the Location" + ddlBranch.Text;
                    Response.Write("<script language='javascript'>window.alert('Mufin Mapping Done " + Server.HtmlEncode(lblMessage.Text) + "');window.location ='pgMufinAdmin.aspx';</script>");
                }
                else
                {
                    lblMessage.Text = "Not Saved Retry!";
                }
            }
            catch(Exception ex)
            {
                Response.Write(ex.Message);
                Response.Write(ex);
            }
            finally
            {
                con.Close();
            }
        }