C# 如何手动将项目添加到中继器控件
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How to add item to Repeater control manually
提问by dragonfly
First of all:
首先：
- _ddlOptions is drop down list
- _selectedOptions is repeater control
- _ddlOptions 是下拉列表
- _selectedOptions 是中继器控制
and it's just provisional code of my final control.
它只是我最终控制的临时代码。
What I want to do is to get data for _ddlOption on !IsPostBack. There is Add button that enables user to move selected drop down item to repeater control.
我想要做的是在 !IsPostBack 上获取 _ddlOption 的数据。有添加按钮，使用户能够将选定的下拉项目移动到中继器控件。
It the following way of updating Repeater.Items correct? I found many solution of adding/removing elements manually using DataSource, but here my DataSource is null, as I set it only on !IsPostBack.
以下更新Repeater.Items的方式正确吗？我找到了许多使用 DataSource 手动添加/删除元素的解决方案，但这里我的 DataSource 为空，因为我仅将它设置在 !IsPostBack 上。
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
_ddlOptions.DataSource = new[] { 1, 2, 3 };
_ddlOptions.DataBind();
}
}
protected void OnAdd(object sender, EventArgs e)
{
var list = new ArrayList(_selectedOptions.Items);
list.Add(_ddlOptions.SelectedItem);
_ddlOptions.Items.RemoveAt(_ddlOptions.SelectedIndex);
_selectedOptions.DataSource = list;
_selectedOptions.DataBind();
}
采纳答案by Patrick
If you only need to fetch data once and you're going to use viewstate, get the data first time you need it, store it in VS and get it from VS for all future PostBacks.
如果您只需要获取一次数据并且打算使用视图状态，请在第一次需要时获取数据，将其存储在 VS 中，然后从 VS 获取以供以后所有回传。
Example:
例子：
public List<int> Data
{
get
{
if (ViewState["Data"] == null)
{
// Get your data, save it and return it.
var data = new List<int> { 1, 2, 3 };
ViewState["Data"] = data;
return data;
}
return (List<int>)ViewState["Data"];
}
set
{
ViewState["Data"] = value;
}
}
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindData(Data);
}
}
private void BindData(List<int> data)
{
_ddlOptions.DataSource = data;
_ddlOptions.DataBind();
}
protected void OnAdd(object sender, EventArgs e)
{
var existing = Data;
existing.Add(_ddlOptions.SelectedItem);
_ddlOptions.Items.RemoveAt(_ddlOptions.SelectedIndex);
Data = existing;
BindData(existing);
}
I didn't test this - and its only my first thought but you can build on it from here.
我没有测试这个 - 这只是我的第一个想法，但你可以从这里开始。
Patrick.
帕特里克。
回答by James Campbell
You can use a DataAdapter to fill a table in a DataSet.
您可以使用 DataAdapter 来填充 DataSet 中的表。
DataSet ds = new DataSet();
using (SqlConnection conn = YourConnectionFactory.GetConnection())
{
SqlCommand objComm = DBHelper.CreateStoredProc("YourStoredProcedure",
conn);
SqlDataAdapter adapt = new SqlDataAdapter(objComm);
adapt.Fill(ds, TableName);
conn.Close();
}
DataTable dt = ds.Tables[0];
for (int a=dt.Rows.Count-1; a>= 0; a--)
{
// check and insert as necessary
}
YourControl.DataSource = ds;
YourControl.DataBind();
You can also do something like this then,
like rebind Taken from: http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.repeater.aspx:
然后你也可以做这样的事情，
比如重新绑定取自：http: //msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.repeater.aspx：
Dim values As New ArrayList()
values.Add(New PositionData("Microsoft", "Msft"))
values.Add(New PositionData("Intel", "Intc"))
values.Add(New PositionData("Dell", "Dell"))
Repeater1.DataSource = values Repeater1.DataBind()
Repeater2.DataSource = values Repeater2.DataBind()
回答by Ian Jacobs
Looks good to me. You just may want to move the decalration for your list outside the onAdd method. As you have it I think it will be reinitialized every time the add button is clicked, so you'll never have more than the currently selected item in your repeater.
在我看来很好。您可能只想将列表的声明移动到 onAdd 方法之外。正如您所拥有的，我认为每次单击添加按钮时它都会重新初始化，因此您的中继器中永远不会超过当前选定的项目。
