如何根据项目自动选择下拉列表项目'；s文本

我已将leaveID、leavename和type name保存到数据库中。

现在，当我选择leaveID时，我想自动填写休假名称（文本框）和类型名称（下拉列表）。问题是，当我选择下拉列表LeaveID时，Leave Name（文本框）会自动填充，但typename（下拉列表）不会填充。我的ddlid_SelectedIndexChanged事件处理程序是

protected void ddlid_SelectedIndexChanged(object sender, EventArgs e)
{
    string str = "select leavename from LeaveType where leaveID='" + 
                 ddlid.SelectedItem.Text + "'";
    SqlDataReader dr = conn.query(str);
    if (dr.Read())
    {
        txtid.Text = dr[0].ToString();//VALUE FILLS AUTOMATICALLY ACCORDING TO SELECTED ID
    }
    string str1 = "select TypeName from Leavetype where LeaveID='"+
                  ddlid.SelectedItem.Text+"'";
    SqlDataReader dr1 = conn.query(str1);
    if (dr1.Read())
    {
        ddltype.SelectedItem.Text= dr1[0].ToString();//VALUE NOT FILLS AUTOMATICALLY ACCORDING TO SELECTED ID
    }
}

ddlType.SelectedValue = ddlType.Items.FindByText(dr1[0].ToString()).Value;