处理Gridview中动态创建按钮中的事件

我在gridview中创建了动态textboxs和dropdownlist。它工作得很好。此外，我想在动态dropdownlist中触发事件并执行一些操作。

private ArrayList GetDummyData() {  
    ArrayList arr = new ArrayList();  
    arr.Add(new ListItem("Item1", "1"));  
    arr.Add(new ListItem("Item2", "2"));  
    arr.Add(new ListItem("Item3", "3"));  
    arr.Add(new ListItem("Item4", "4"));  
    arr.Add(new ListItem("Item5", "5"));  
    return arr;  
}  
private void FillDropDownList(DropDownList ddl) {  
    ArrayList arr = GetDummyData();  
    foreach (ListItem item in arr) {  
        ddl.Items.Add(item);  
    }  
}  
private void SetInitialRow() {  
    DataTable dt = new DataTable();  
    DataRow dr = null;  
    dt.Columns.Add(new DataColumn("RowNumber", typeof(string)));  
    dt.Columns.Add(new DataColumn("Column1", typeof(string)));//for TextBox value   
    dt.Columns.Add(new DataColumn("Column2", typeof(string)));//for TextBox value   
    dt.Columns.Add(new DataColumn("Column3", typeof(string)));//for DropDownList selected item   
    dt.Columns.Add(new DataColumn("Column4", typeof(string)));//for DropDownList selected item   
    dr = dt.NewRow();  
    dr["RowNumber"] = 1;  
    dr["Column1"] = string.Empty;  
    dr["Column2"] = string.Empty;  
    dt.Rows.Add(dr);  
    //Store the DataTable in ViewState for future reference   
    ViewState["CurrentTable"] = dt;  
    //Bind the Gridview   
    Gridview1.DataSource = dt;  
    Gridview1.DataBind();  
    //After binding the gridview, we can then extract and fill the DropDownList with Data   
    DropDownList ddl1 = (DropDownList)Gridview1.Rows[0].Cells[3].FindControl("DropDownList1");  
    DropDownList ddl2 = (DropDownList)Gridview1.Rows[0].Cells[4].FindControl("DropDownList2");  
    FillDropDownList(ddl1);  
    FillDropDownList(ddl2);  
}  
private void AddNewRowToGrid() {  
    if (ViewState["CurrentTable"] != null) {  
        DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];  
        DataRow drCurrentRow = null;  
        if (dtCurrentTable.Rows.Count > 0) {  
            drCurrentRow = dtCurrentTable.NewRow();  
            drCurrentRow["RowNumber"] = dtCurrentTable.Rows.Count + 1;  
            //add new row to DataTable   
            dtCurrentTable.Rows.Add(drCurrentRow);  
            //Store the current data to ViewState for future reference   
            ViewState["CurrentTable"] = dtCurrentTable;  

            for (int i = 0; i < dtCurrentTable.Rows.Count - 1; i++) {  
                //extract the TextBox values   
                TextBox box1 = (TextBox)Gridview1.Rows[i].Cells[1].FindControl("TextBox1");  
                TextBox box2 = (TextBox)Gridview1.Rows[i].Cells[2].FindControl("TextBox2");  
                dtCurrentTable.Rows[i]["Column1"] = box1.Text;  
                dtCurrentTable.Rows[i]["Column2"] = box2.Text;  
                //extract the DropDownList Selected Items   
                DropDownList ddl1 = (DropDownList)Gridview1.Rows[i].Cells[3].FindControl("DropDownList1");  
                DropDownList ddl2 = (DropDownList)Gridview1.Rows[i].Cells[4].FindControl("DropDownList2");  
                // Update the DataRow with the DDL Selected Items   
                dtCurrentTable.Rows[i]["Column3"] = ddl1.SelectedItem.Text;  
                dtCurrentTable.Rows[i]["Column4"] = ddl2.SelectedItem.Text;  
            }  
            //Rebind the Grid with the current data to reflect changes   
            Gridview1.DataSource = dtCurrentTable;  
            Gridview1.DataBind();  
        }  
    }  
    else {  
        Response.Write("ViewState is null");  
    }  
    //Set Previous Data on Postbacks   
    SetPreviousData();  
}  
private void SetPreviousData() {  
    int rowIndex = 0;  
    if (ViewState["CurrentTable"] != null) {  
        DataTable dt = (DataTable)ViewState["CurrentTable"];  
        if (dt.Rows.Count > 0) {  
            for (int i = 0; i < dt.Rows.Count; i++) {  
                TextBox box1 = (TextBox)Gridview1.Rows[i].Cells[1].FindControl("TextBox1");  
                TextBox box2 = (TextBox)Gridview1.Rows[i].Cells[2].FindControl("TextBox2");  
                DropDownList ddl1 = (DropDownList)Gridview1.Rows[rowIndex].Cells[3].FindControl("DropDownList1");  
                DropDownList ddl2 = (DropDownList)Gridview1.Rows[rowIndex].Cells[4].FindControl("DropDownList2");  
                //Fill the DropDownList with Data   
                FillDropDownList(ddl1);  
                FillDropDownList(ddl2);  
                if (i < dt.Rows.Count - 1) {  
                    //Assign the value from DataTable to the TextBox   
                    box1.Text = dt.Rows[i]["Column1"].ToString();  
                    box2.Text = dt.Rows[i]["Column2"].ToString();  
                    //Set the Previous Selected Items on Each DropDownList  on Postbacks   
                    ddl1.ClearSelection();  
                    ddl1.Items.FindByText(dt.Rows[i]["Column3"].ToString()).Selected = true;  
                    ddl2.ClearSelection();  
                    ddl2.Items.FindByText(dt.Rows[i]["Column4"].ToString()).Selected = true;  
                }  
                rowIndex++;  
            }  
        }  
    }  
}  
protected void Page_Load(object sender, EventArgs e) {  
    if (!Page.IsPostBack) {  
        SetInitialRow();  
    }  
}  
protected void ButtonAdd_Click(object sender, EventArgs e) {  
    AddNewRowToGrid();  
}  
protected void Gridview1_RowCreated(object sender, GridViewRowEventArgs e) {  
    if (e.Row.RowType == DataControlRowType.DataRow) {  
        DataTable dt = (DataTable)ViewState["CurrentTable"];  
        LinkButton lb = (LinkButton)e.Row.FindControl("LinkButton1");  
        if (lb != null) {  
            if (dt.Rows.Count > 1) {  
                if (e.Row.RowIndex == dt.Rows.Count - 1) {  
                    lb.Visible = false;  
                }  
            }  
            else {  
                lb.Visible = false;  
            }  
        }  
    }  
}  
protected void LinkButton1_Click(object sender, EventArgs e) {  
    LinkButton lb = (LinkButton)sender;  
    GridViewRow gvRow = (GridViewRow)lb.NamingContainer;  
    int rowID = gvRow.RowIndex;  
    if (ViewState["CurrentTable"] != null) {  
        DataTable dt = (DataTable)ViewState["CurrentTable"];  
        if (dt.Rows.Count > 1) {  
            if (gvRow.RowIndex < dt.Rows.Count - 1) {  
                //Remove the Selected Row data and reset row number  
                dt.Rows.Remove(dt.Rows[rowID]);  
                ResetRowID(dt);  
            }  
        }  
        //Store the current data in ViewState for future reference  
        ViewState["CurrentTable"] = dt;  
        //Re bind the GridView for the updated data  
        Gridview1.DataSource = dt;  
        Gridview1.DataBind();  
    }  
    //Set Previous Data on Postbacks  
    SetPreviousData();  
}  
private void ResetRowID(DataTable dt) {  
    int rowNumber = 1;  
    if (dt.Rows.Count > 0) {  
        foreach (DataRow row in dt.Rows) {  
            row[0] = rowNumber;  
            rowNumber++;  
        }  
    }  
}