我一直试图找出一种动态呈现数据的方法，但一直没有运气。 我有一个警报系统（由一个SQL Server数据库表组成），然后我想要该表中的每个（相关）行，构建一个要在ASP页面中显示的字符串，并插入一个checkBox（只是所以我可以将警报标记为“已读”。
我已经拥有了所有数据（我认为我正确地做了），但完全无法以我想要的方式在页面上显示这些数据。
这是C＃代码：
protected void getAlertas(string matricula)
{
string query = "SELECT * FROM ALERTAS A ";
query += "WHERE EXISTS ( ";
query += "SELECT ID, MATRICULA FROM VEICULOS V WHERE V.MATRICULA = @matricula ";
query += "AND A.IDVEICULO = V.ID ";
query += "AND LIDA = 0)";
SqlCommand comm = new SqlCommand(query, Utils.connectDB());
matricula = matricula.ToString().Replace("\"", "'");
comm.Parameters.AddWithValue("@matricula", matricula);
StringBuilder builder = new StringBuilder();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter();
StringCollection alertValues = new StringCollection();
StringBuilder HTML = new StringBuilder();
try
{
comm.Connection.Open();
SqlDataReader reader = comm.ExecuteReader();
dt.Load(reader);
foreach (DataRow row in dt.Rows)
{
Label label = new Label();
CheckBox cBox = new CheckBox();
foreach (DataColumn column in dt.Columns)
{
alertValues.Add(row[column].ToString());
}
builder.Append(alertValues[0]); //ID do alerta
builder.Append(":");
builder.Append(matricula);
if (int.Parse(alertValues[10]) == 0) //se motor desligado
{
//string output = "Motor desligado às " + alertValues[3] + "do dia " + alertValues[4];
builder.Append("Motor desligado às ");
}
else if(int.Parse(alertValues[10]) == 1) //se motor ligado
{
//string output = "Motor ligado às " + alertValues[3] + "do dia " + alertValues[4];
builder.Append("Motor ligado às ");
}
builder.Append(alertValues[3]); //hora
builder.Append("do dia ");
builder.Append(alertValues[4]); //data
//HTML.Append(" <div id=\"notifications\" runat=\"server\" class=\"notifications\">");
//HTML.Append(" <div class=\"notificationText\">");
//HTML.Append("<asp:Label ID=\"Label1\" runat=\"server\" Text=\"" + builder.ToString() + "\"></asp:Label>");
//HTML.Append("</div>");
//HTML.Append("<div class=\"setRead\">");
//HTML.Append("<asp:CheckBox ID=\"" + alertValues[0] + "\" runat=\"server\" />");
//HTML.Append("</div>");
//HTML.Append("</div>");
label.Text = builder.ToString();
cBox.ID = alertValues[0];
}
}
finally
{
comm.Connection.Close();
}
}
这是我想要呈现数据的ASP页面：
<div id="contentRight">
<div id="head">
<p>
<b>Notificações</b></p>
</div>
<div id="notifications" runat="server" class="notifications">
<div class="notificationText">
<asp:Label ID="Label1" runat="server" Text="Nada para mostrar"></asp:Label>
</div>
<div class="setRead">
<asp:CheckBox ID="AlertIDRead" runat="server" />
</div>
</div>
<hr />
<div id="OkBtn" align="center">
<asp:Button ID="OkButton" class="Button" runat="server" Text="Ok" />
</div>
</div>
目标是能够将构造的字符串呈现给页面，并且对于这些行中的每一行，还提供一个CheckBox，其具有与alertID相同的ID（在DB上），仅为了简化将它们标记为已读。
我真的迷失在这里，可以使用一些帮助。
答案 0 :(得分：1)
您可以动态添加项目。然而，这有点痛苦。您必须每次添加它们，而不仅仅是第一次加载页面。此外，如果您希望在回发之间保留视图状态并记住检查了哪些框，则需要在页面生命周期的早期添加它们（例如，在Page_Init事件中）。
更简单的方法是使用ListView之类的控件。在ASP.NET 4.0中，您可以根据需要轻松获取控件名称，但您可能对ASP.NET 3.5中自动生成的控件名称没有问题。以下是ASPX页面的示例：
<asp:ListView runat="server" ID="listView" DataKeyNames="AlertId">
<LayoutTemplate>
<div id="contentRight">
<div id="head">
<p>
<b>Notificações</b></p>
</div>
<div id="notifications" runat="server" class="notifications">
<asp:PlaceHolder ID="itemPlaceholder" runat="server" />
</div>
</div>
</LayoutTemplate>
<ItemTemplate>
<div class="notificationText">
<asp:Label ID="Label1" runat="server" Text='<%#Eval("AlertText")%>' />
</div>
<div class="setRead">
<asp:CheckBox ID="AlertChecked" runat="server" />
</div>
</ItemTemplate>
</asp:ListView>
<hr />
<div id="OkBtn" align="center">
<asp:Button ID="OkButton" class="Button" runat="server" Text="Ok" onclick="OkButton_Click" />
</div>
<asp:Label runat="server" ID="lblDisplay" />
这里有一些示例代码隐藏。请注意，我已使用硬编码列表替换了数据访问代码。我假设您很乐意用从数据库加载数据所需的代码替换它。
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
// Creates a list of alerts and binds them to the list view.
// You would use your sql data reader here instead. You could convert the data
// into a list or just bind the data reader directly to the list view. If you
// bind the data reader to the list view then be sure to update the Eval statements
// in the list view templates.
var alerts = new[]
{
new { AlertId = 1, AlertText = "This is alert #1."},
new { AlertId = 2, AlertText = "This is the second alert."},
new { AlertId = 3, AlertText = "This is the third alert."},
new { AlertId = 5, AlertText = "This is alert #5."}
};
listView.DataSource = alerts;
listView.DataBind();
}
}
protected void OkButton_Click(object sender, EventArgs e)
{
// get the list of alerts that have been checked
var checkedAlerts = new List<int>();
foreach (var listViewItem in listView.Items)
{
var checkbox = (CheckBox)listViewItem.FindControl("AlertChecked");
if (checkbox.Checked)
{
checkedAlerts.Add((int)listView.DataKeys[listViewItem.DataItemIndex].Value);
}
}
// now do something to record them as read; we'll just display them in a label for this sample.
lblDisplay.Text = "The following alerts were marked read: " + String.Join(",", checkedAlerts);
}