GridView 動態綁定控件 OnRowCommand事件觸發

主題：GridView動態生成的控件不能觸發OnRowCommand事件，且點擊控件按鈕后，控件的值會消失。

案例，

由於公司需要綁定的數據列順序是動態生成的，且有的數據列需要綁定Button控件。所以需要動態綁定TemplateField。

問題，不能觸發OnRowCommand事件和點擊控件按鈕后，控件的列值會消失。

不能觸發OnRowCommand代碼如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;

namespace WebApplication1
{
    public partial class _Default : System.Web.UI.Page
    {
        //protected override void OnInit(EventArgs e)
        //{

        //    TemplateField customField = new TemplateField();

        //    customField.ShowHeader = true;
        //    customField.HeaderTemplate = new GridViewTemplate(DataControlRowType.Header, "動態添加列");
        //    GridViewTemplate gvt = new GridViewTemplate(DataControlRowType.DataRow, "lbtn", "Name");
        //    customField.ItemTemplate = gvt;
        //    ContactsGridView.Columns.Add(customField);//添加編輯按鈕到gridview
        //}

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                TemplateField customField = new TemplateField();

                customField.ShowHeader = true;
                customField.HeaderTemplate = new GridViewTemplate(DataControlRowType.Header, "動態添加列");
                GridViewTemplate gvt = new GridViewTemplate(DataControlRowType.DataRow, "lbtn", "Name");
                customField.ItemTemplate = gvt;
                ContactsGridView.Columns.Add(customField);//添加編輯按鈕到gridview

                DataTable dt = new System.Data.DataTable();
                dt.Columns.Add("data1");
                dt.Columns.Add("ContactID");

                DataRow dr = dt.NewRow();
                dr["data1"] = "test";
                dr["ContactID"] = "ContactID";
                dt.Rows.Add(dr);

                DataRow dr2 = dt.NewRow();
                dr2["data1"] = "test2";
                dr2["ContactID"] = "ContactID";
                dt.Rows.Add(dr2);

                ContactsGridView.DataSource = dt;
                ContactsGridView.DataBind();
            }
        }

       
        public class GridViewTemplate : ITemplate
        {
            public delegate void EventHandler(object sender, EventArgs e);
            public event EventHandler eh;

            private DataControlRowType templateType;

            private string columnName;
            private string controlID;


            public GridViewTemplate(DataControlRowType type, string colname)
            {

                templateType = type;

                columnName = colname;

            }
            public GridViewTemplate(DataControlRowType type, string controlID, string colname)
            {
                templateType = type;
                this.controlID = controlID;
                columnName = colname;
            }


            public void InstantiateIn(System.Web.UI.Control container)
            {
                switch (templateType)
                {
                    case DataControlRowType.Header:
                        LinkButton lc = new LinkButton();
                        lc.Text = columnName;
                        container.Controls.Add(lc);
                        break;
                    case DataControlRowType.DataRow:
                        LinkButton lbtn = new LinkButton();
                        lbtn.ID = "id1";
                        lbtn.Text = "test";
                       // lbtn.ID = this.controlID;
                        //if (eh != null)
                        //{
                        //    lbtn.Click += new System.EventHandler(eh);
                        //}
                       // lbtn.DataBinding += new System.EventHandler(lbtn_DataBinding);

                        container.Controls.Add(lbtn);

                        break;
                    default:
                        break;
                }
            }

        }

        protected void ContactsGridView_OnRowDataBound(Object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType==DataControlRowType.DataRow)
            {
                LinkButton lb = e.Row.FindControl("id1") as LinkButton;
                lb.CommandArgument = "1";
            }

        }

        protected void ContactsGridView_RowCommand(Object sender, GridViewCommandEventArgs e)
        {
            // If multiple buttons are used in a GridView control, use the
            // CommandName property to determine which button was clicked.
            if (e.CommandName == "Add")
            {
                // Convert the row index stored in the CommandArgument
                // property to an Integer.
                int index = Convert.ToInt32(e.CommandArgument);

                // Retrieve the row that contains the button clicked 
                // by the user from the Rows collection.
                GridViewRow row = ContactsGridView.Rows[index];

                // Create a new ListItem object for the contact in the row.     
                ListItem item = new ListItem();
                item.Text = Server.HtmlDecode(row.Cells[2].Text) + " " +
                Server.HtmlDecode(row.Cells[3].Text);
            }
        }
    }
}

后來把數據綁定從Page.IsPostBack移出，是可以觸發OnRowCommand事件。但是點擊的時候都要重新做GridView的查詢，效率會比較差。

  protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
               
            }

            TemplateField customField = new TemplateField();

            customField.ShowHeader = true;
            customField.HeaderTemplate = new GridViewTemplate(DataControlRowType.Header, "動態添加列");
            GridViewTemplate gvt = new GridViewTemplate(DataControlRowType.DataRow, "lbtn", "Name");
            customField.ItemTemplate = gvt;
            ContactsGridView.Columns.Add(customField);//添加編輯按鈕到gridview

            DataTable dt = new System.Data.DataTable();
            dt.Columns.Add("data1");
            dt.Columns.Add("ContactID");

            DataRow dr = dt.NewRow();
            dr["data1"] = "test";
            dr["ContactID"] = "ContactID";
            dt.Rows.Add(dr);

            DataRow dr2 = dt.NewRow();
            dr2["data1"] = "test2";
            dr2["ContactID"] = "ContactID";
            dt.Rows.Add(dr2);

            ContactsGridView.DataSource = dt;
            ContactsGridView.DataBind();
        }

最終解決方法，

1.用BoundField替代TemplateField方法，代碼如下。

 ButtonField adup = new ButtonField();
adup.ButtonType = ButtonType.Link;
 adup.HeaderText = "廣告上架";
 adup.Text = "test";
adup.CommandName = "shangjia";
 ContactsGridView.Columns.Add(adup);//添加編輯按鈕到gridview

 

2.重新寫OnInit方法。在OnInit上綁定TemplateField，可以觸發OnRowCommand事件。

        protected override void OnInit(EventArgs e)
        {

            TemplateField customField = new TemplateField();

            customField.ShowHeader = true;
            customField.HeaderTemplate = new GridViewTemplate(DataControlRowType.Header, "動態添加列");
            GridViewTemplate gvt = new GridViewTemplate(DataControlRowType.DataRow, "lbtn", "Name");
            customField.ItemTemplate = gvt;
            ContactsGridView.Columns.Add(customField);//添加編輯按鈕到gridview
        }

2, 

動態綁定控件不能觸發的估計原因是：

1）用TemplateField動態綁定的控件不是服務器端控件，不在ViewState記錄，所以刷新頁面后，這些列的值會消失，OnRowCommand事件自然也不會觸發。

2）而用BoundField，會記錄ViewState，所以刷新頁面后，就會觸發事件OnRowCommand。

3）在OnInit上綁定控件,首先會初始化綁定控件和事件（OnRowCommand重新綁定了）。這樣OnRowCommand事件也會觸發。