我无法弄清楚为什么我使用这些方法中的任何一种 (load_qc_form(); enable_qc_form();disable_qc_form();) 我得到“消息：对象引用未设置为对象的实例”。信息。
调用方法如何返回null？
这是我的整个代码。我是 C# 新手，正在尝试更新现有页面。有人能指出我正确的方向吗？
我希望能够从应用程序中的任何位置调用这些方法。
namespace test_page
{
using System;
//using System.Windows.Forms;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
/// <summary>
/// Summary description for ProductionQC.
/// </summary>
///
public class hendrix : System.Web.UI.UserControl
{
#region class_variable_declarations
//Test Boxes
protected System.Web.UI.WebControls.TextBox boxOrder;
protected System.Web.UI.WebControls.TextBox boxBox;
protected System.Web.UI.WebControls.TextBox boxPallet;
protected System.Web.UI.WebControls.TextBox boxPulpTemp;
protected System.Web.UI.WebControls.TextBox boxComments;
protected System.Web.UI.WebControls.TextBox boxMajdef1;
protected System.Web.UI.WebControls.TextBox boxMajdef2;
protected System.Web.UI.WebControls.TextBox boxMajdef3;
protected System.Web.UI.WebControls.TextBox boxMindef1;
protected System.Web.UI.WebControls.TextBox boxMindef2;
protected System.Web.UI.WebControls.TextBox boxMindef3;
protected System.Web.UI.WebControls.TextBox boxSamples;
//drop down lists
protected System.Web.UI.WebControls.DropDownList listYN;
protected System.Web.UI.WebControls.DropDownList listMaj1;
protected System.Web.UI.WebControls.DropDownList listMaj2;
protected System.Web.UI.WebControls.DropDownList listMaj3;
protected System.Web.UI.WebControls.DropDownList listMin1;
protected System.Web.UI.WebControls.DropDownList listMin2;
protected System.Web.UI.WebControls.DropDownList listMin3;
protected System.Web.UI.WebControls.DropDownList listRecorder;
//labels
protected System.Web.UI.WebControls.Label lblPalletTag;
protected System.Web.UI.WebControls.Label lblmajdef1;
protected System.Web.UI.WebControls.Label lblmajdef2;
protected System.Web.UI.WebControls.Label lblmajdef3;
protected System.Web.UI.WebControls.Label lblmindef1;
protected System.Web.UI.WebControls.Label lblmindef2;
protected System.Web.UI.WebControls.Label lblmindef3;
protected System.Web.UI.WebControls.Label lblPulpTemp;
protected System.Web.UI.WebControls.Label lblComments;
protected System.Web.UI.WebControls.Label lblPackageCorrect;
protected System.Web.UI.WebControls.Label lblTotSamples;
protected System.Web.UI.WebControls.Label lblrecorder;
//Buttons
protected System.Web.UI.WebControls.Button btnGo;
protected System.Web.UI.WebControls.Button btnGo2;
protected System.Web.UI.WebControls.Button btnGo3;
protected System.Web.UI.WebControls.Button btnClear;
//Gridviews
protected System.Web.UI.WebControls.GridView grdDisplayOrd;
protected System.Web.UI.WebControls.GridView grdDisplayBox;
//Data connections - adapters
protected System.Data.SqlClient.SqlCommand cmdData;
protected System.Data.SqlClient.SqlConnection sqlConnection1;
protected System.Data.SqlClient.SqlDataReader dataReader;
#endregion class_variable_declarations
private void Page_Load(object sender, System.EventArgs e)
{
//initializePage();
// Put user code to initialize the page here
if (!this.Page.IsPostBack)
{
//load_qc_form();
//disable_qc_form();
}
}
//private void initializePage()
// {
// throw new NotImplementedException();
//}
#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.sqlConnection1 = new System.Data.SqlClient.SqlConnection();
this.btnGo.Click += new System.EventHandler(this.btnGo_Click);
this.btnGo2.Click += new System.EventHandler(this.btnGo2_Click);
// this.btnGo3.Click += new System.EventHandler(this.btnGo3_Click);
this.btnClear.Click += new EventHandler(this.btnClear_Click);
//
// sqlConnection1
//
this.sqlConnection1.ConnectionString = "workstation id=\"******";packet size=4096;user id=******;data source=\"******";persis" +
"t security info=True;initial catalog=****;password=**********";
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
// public virtual string DisplayMember { get; set; }
//get and display order data
private void btnGo_Click(object sender, System.EventArgs e)
{
{
SqlCommand cmd = new SqlCommand();
cmd.CommandText = "Select ord.order_number as Order#,var.description as Description,grd.description as Grade, " +
"size.description as Size,pkg.description as Pkg, ord.container_type as Pallet " +
"FROM t_item_master itm INNER JOIN t_order_detail ord (NOLOCK) ON ord.item_number = itm.item_number " +
"LEFT OUTER JOIN t_package pkg (NOLOCK) ON pkg.package_name = itm.product_package_code " +
"LEFT OUTER JOIN t_grade grd (NOLOCK) ON grd.grade_id = itm.grade_id " +
"LEFT OUTER JOIN t_size size (NOLOCK) ON size.size_id = itm.size_id AND size.package_id = pkg.package_id " +
"LEFT OUTER JOIN t_variety var (NOLOCK) ON var.variety_id = itm.variety_id " +
"WHERE order_number like @order_number";
cmd.Parameters.Add("@order_number", SqlDbType.VarChar).Value = boxOrder.Text;
cmd.CommandType = CommandType.Text;
cmd.Connection = this.sqlConnection1;
this.sqlConnection1.Open();
this.grdDisplayOrd.Visible = true;
SqlDataAdapter adpt = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
adpt.Fill(ds);
grdDisplayOrd.DataSource = ds;
grdDisplayOrd.DataBind();
this.sqlConnection1.Close();
}
}
// get and display box data
private void btnGo2_Click(object sender, System.EventArgs e)
{
{
load_qc_form();
SqlCommand cmd = new SqlCommand();
HyperLink test_link1 = new HyperLink();
cmd.CommandText = "select " +
"item_number as Item#, " +
"description as Desctiption, " +
"grower_lot as Lot#, " +
"pack_date as Packed " +
"from v_box_data where box_id = @box_id";
cmd.Parameters.Add("@box_id", SqlDbType.VarChar).Value = boxBox.Text;
cmd.CommandType = CommandType.Text;
cmd.Connection = this.sqlConnection1;
this.sqlConnection1.Open();
this.grdDisplayBox.Visible = true;
SqlDataAdapter adpt = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
adpt.Fill(ds);
grdDisplayBox.DataSource = ds;
grdDisplayBox.DataBind();
this.sqlConnection1.Close();
}
}
private void load_qc_form()
{
#region declare_variables
// string pallet_tag;
//string correct_package;
//string total_samples;
//string majdef1;
//string majdef2;
//string majdef3;
// string mindef1;
// string mindef2;
// string mindef3;
// string majcnt1;
// string majcnt2;
//string majcnt3;
// string mincnt1;
// string mincnt2;
// string mincnt3;
// string pulptemp;
// string comments;
string recorder;
#endregion declare_variables
#region fill_list_recorder
try
{
listRecorder.Items.Clear();
recorder = "select EMPID,FIRSTNAME+' '+LASTNAME from t_famous_employee " +
"where COSTCENTERNAME like 'Quality Control - 2011' " +
"and HOMECREWID LIKE 'Shipping' ";
cmdData = new System.Data.SqlClient.SqlCommand(recorder, this.sqlConnection1);
cmdData.Connection = this.sqlConnection1;
this.sqlConnection1.Open();
SqlDataAdapter da = new SqlDataAdapter(cmdData);
DataTable dt = new DataTable();
da.Fill(dt);
listRecorder.DataBind();
listRecorder.DataSource = dt;
listRecorder.DataValueField = "EMPID";
listRecorder.DataTextField = "FIRSTNAME+' '+LASTNAME";
this.listRecorder.Items.Insert(0, "FIRSTNAME+' '+LASTNAME");
}
catch (Exception) { }
this.dataReader.Close();
#endregion
}
private void btnGo3_Click(object sender, System.EventArgs e)
{
{
}
}
private void btnClear_Click(object sender, System.EventArgs e)
{
{
this.boxOrder.Text = "";
this.boxBox.Text = "";
this.grdDisplayOrd.Visible = false;
this.grdDisplayBox.Visible = false;
//disable_qc_form();
}
}
private void enable_qc_form()
{
this.listMaj1.Enabled = true;
this.listMaj2.Enabled = true;
this.listMaj3.Enabled = true;
this.listMin1.Enabled = true;
this.listMin2.Enabled = true;
this.listMin3.Enabled = true;
this.listYN.Enabled = true;
this.listMaj1.Enabled = true;
this.listMaj2.Enabled = true;
this.listMaj3.Enabled = true;
this.listMin1.Enabled = true;
this.listMin2.Enabled = true;
this.listMin3.Enabled = true;
this.boxComments.Enabled = true;
this.boxMajdef1.Enabled = true;
this.boxMajdef2.Enabled = true;
this.boxMajdef3.Enabled = true;
this.boxMindef1.Enabled = true;
this.boxMindef2.Enabled = true;
this.boxMindef3.Enabled = true;
this.boxPallet.Enabled = true;
this.boxPulpTemp.Enabled = true;
this.boxSamples.Enabled = true;
this.lblComments.Enabled = true;
this.lblmajdef1.Enabled = true;
this.lblmajdef2.Enabled = true;
this.lblmajdef3.Enabled = true;
this.lblmindef1.Enabled = true;
this.lblmindef2.Enabled = true;
this.lblmindef3.Enabled = true;
this.lblPackageCorrect.Enabled = true;
this.lblPalletTag.Enabled = true;
this.lblPulpTemp.Enabled = true;
this.lblTotSamples.Enabled = true;
}
private void disable_qc_form()
{
this.listMaj1.Enabled = false;
this.listMaj2.Enabled = false;
this.listMaj3.Enabled = false;
this.listMin1.Enabled = false;
this.listMin2.Enabled = false;
this.listMin3.Enabled = false;
this.listYN.Enabled = false;
this.listMaj1.Enabled = false;
this.listMaj2.Enabled = false;
this.listMaj3.Enabled = false;
this.listMin1.Enabled = false;
this.listMin2.Enabled = false;
this.listMin3.Enabled = false;
this.boxComments.Enabled = false;
this.boxMajdef1.Enabled = false;
this.boxMajdef2.Enabled = false;
this.boxMajdef3.Enabled = false;
this.boxMindef1.Enabled = false;
this.boxMindef2.Enabled = false;
this.boxMindef3.Enabled = false;
this.boxPallet.Enabled = false;
this.boxPulpTemp.Enabled = false;
this.boxSamples.Enabled = false;
this.lblComments.Enabled = false;
this.lblmajdef1.Enabled = false;
this.lblmajdef2.Enabled = false;
this.lblmajdef3.Enabled = false;
this.lblmindef1.Enabled = false;
this.lblmindef2.Enabled = false;
this.lblmindef3.Enabled = false;
this.lblPackageCorrect.Enabled = false;
this.lblPalletTag.Enabled = false;
this.lblPulpTemp.Enabled = false;
this.lblTotSamples.Enabled = false;
}
}
}
所以我需要能够调用该方法来测试我的第一个下拉列表。
预先感谢您的帮助！！