在asp.net的html表中添加下拉列表

Posted 2023-03-05

【中文标题】在asp.net的html表中添加下拉列表

【英文标题】：Adding dropdown list in html table in asp.net

【发布时间】：2018-07-31 14:26:52

【问题描述】：

我正在从数据库中填充 ID 和值并绑定到下拉列表。我想将下拉列表添加到后面代码中为第 2 列的每一行生成的 html 表中。我为下拉列表提供了不同的 id，但它似乎不起作用，只有最后一行获取下拉列表。

如果我不填充数据而只使用 id 属性，则下拉列表会出现在表格的每一行中。同样，如果我将项目随机添加到下拉列表中，那么事情就会再次起作用。但它不适用于绑定数据。

下面是我的代码：

.cs

protected void Page_Load(object sender, EventArgs e)
        
            if(!Page.IsPostBack)
            
                // Generate tabel for employer
                PopulateDropDown();
                Displaytable(numOfRows);


            
        

private DropDownList PopulateDropDown()
        
            try
            
                DC.dbConnection = Database.getInstance();
                DC.dbConnection.Open();

                DC.dbCommand = new SqlCommand("SP_Employee", DC.dbConnection);
                DC.dbCommand.CommandType = System.Data.CommandType.StoredProcedure;
                DC.dbCommand.Parameters.AddWithValue("@Action", "SelectEmployeeList");


                lst.DataSource = DC.dbCommand.ExecuteReader();

                lst.DataTextField = "Name";
                lst.DataValueField = "Id";

                lst.DataBind();

                DC.dbConnection.Close();

            catch(Exception ex)
            

            
            return lst;
        


 private void Displaytable(int rowsCount)
        
            try
            

                Table tbl = new Table();
                tbl.ID = "PendingTable";

                tbl.Width = Unit.Percentage(100);
                tbl.Rows.Add(new TableRow());

                tbl.Rows[tbl.Rows.Count - 1].Cells.Add(new TableHeaderCell());
                tbl.Rows[tbl.Rows.Count - 1].Cells[tbl.Rows[tbl.Rows.Count - 1].Cells.Count - 1].Text = "First Name";

                tbl.Rows[tbl.Rows.Count - 1].Cells.Add(new TableHeaderCell());
                tbl.Rows[tbl.Rows.Count - 1].Cells[tbl.Rows[tbl.Rows.Count - 1].Cells.Count - 1].Text = "Last Name";

                tbl.Rows[tbl.Rows.Count - 1].Cells.Add(new TableHeaderCell());
                tbl.Rows[tbl.Rows.Count - 1].Cells[tbl.Rows[tbl.Rows.Count - 1].Cells.Count - 1].Text = "Employer";

                tbl.Rows[tbl.Rows.Count - 1].Cells.Add(new TableHeaderCell());
                tbl.Rows[tbl.Rows.Count - 1].Cells[tbl.Rows[tbl.Rows.Count - 1].Cells.Count - 1].Text = "Email Address";


                const int colsCount = 4;

                for (int i = 0; i < rowsCount; i++)
                
                    TableRow row = new TableRow();

                    for (int j = 0; j < colsCount; j++)
                    
                        TableCell cell = new TableCell();
                        TextBox tb = new TextBox();

                        // Set a unique ID for each TextBox added
                        tb.ID = "TextBoxRow_" + i + "Col_" + j;

                        if (j == 2)
                        
                            DropDownList newlst = new DropDownList();

                            newlst = PopulateDropDown();
                            newlst.ID = Guid.NewGuid().ToString();


                            cell.Controls.Add(newlst);
                            row.Cells.Add(cell);
                        
                        else
                        

                            // Add the control to the TableCell
                            cell.Controls.Add(tb);
                            row.Cells.Add(cell);
                        






                    
                    tbl.Rows.Add(row);
                
                Panel1.Controls.Add(tbl);

            
            catch (Exception ex)
            

            
        

【参考方案1】：

好吧，我只是通过添加项目而不是添加 datatextfield 和 datavaluefield 以某种方式进行管理。所以下面是我如何填充下拉项目并在每一行中显示。

private DropDownList PopulateDropDown()
        
            DropDownList lst = new DropDownList();
            try
            
                DC.dbConnection = Database.getInstance();
                DC.dbConnection.Open();

                DC.dbCommand = new SqlCommand("SP_Employee", DC.dbConnection);
                DC.dbCommand.CommandType = System.Data.CommandType.StoredProcedure;
                DC.dbCommand.Parameters.AddWithValue("@Action", "SelectEmployeeList");

                DC.dbReader = DC.dbCommand.ExecuteReader();

                while(DC.dbReader.Read())
                
                    lst.Items.Add(DC.dbReader["Name"].ToString());
                

                DC.dbConnection.Close();

            catch(Exception ex)
            

            
            return lst;