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[英]Dynamically adding child controls to listview control in ASP.NET C# from code behind file
[英]Programically adding child controls to a asp.net composite control
找不到能直接解决我问题的任何东西,因此希望有人能对此有所启发。
我有两个复合控件,可以将它们称为BudgetTable和BudgetTableItem,其中BudgetTable包含BudgetTableItem的列表。
到目前为止,只要我在HTML视图中添加新的RowItem,所有的东西都可以工作-当我以编程方式添加一个新的RowItem时,它会出现,但不能在回发后保留下来。
我只能假设我正在使用ViewState做一些笨拙的事情,并且会感谢任何指针!
提前致谢。
HTML:
<hea:BudgetTable runat="server" ID="btTest" MaximumFundingAvailable="7000" CssClass="bob">
<Items>
<hea:BudgetTableItem runat="server" Description="Test1" />
<hea:BudgetTableItem runat="server" Description="Test2" />
<hea:BudgetTableItem runat="server" Description="Test3" />
</Items>
</hea:BudgetTable>
后面的代码:
[PersistenceMode(PersistenceMode.InnerProperty)]
[ParseChildren(true)]
public class BudgetTableItem : CompositeControl {
private TextBox _description = new TextBox();
private TextBox _cost = new TextBox();
private CheckBox _heaFunded = new CheckBox();
/*public delegate void AddRow();
public delegate void RemoveRow(BudgetTableItem item);
public event AddRow AddNewRow;
public event RemoveRow RemoveNewRow;*/
public string ItemName {
get {
var viewstate = ViewState["ItemName"];
return (viewstate is string) ? (string)viewstate : "default";
}
set {
ViewState["ItemName"] = value;
}
}
public bool ShowRemoveRow {
get {
var viewstate = ViewState["ShowRemoveRow"];
return (viewstate != null && viewstate is bool) ? (bool)viewstate : false;
}
set {
ViewState["ShowRemoveRow"] = value;
}
}
public bool ShowAddRow {
get {
var viewstate = ViewState["ShowAddRow"];
return (viewstate != null && viewstate is bool) ? (bool)viewstate : false;
}
set {
ViewState["ShowAddRow"] = value;
}
}
public string Description {
get {
return _description.Text;
}
set {
_description.Text = value;
}
}
public decimal Cost {
get {
decimal cost =0;
decimal.TryParse(_cost.Text, out cost);
return cost;
}
set {
_cost.Text = value.ToString();
}
}
public bool HeaFunded {
get {
return _heaFunded.Checked;
}
set {
_heaFunded.Checked = value;
}
}
protected override void CreateChildControls() {
Controls.Clear();
HtmlTableCell tableCell1 = new HtmlTableCell();
HtmlTableCell tableCell2 = new HtmlTableCell();
HtmlTableCell tableCell3 = new HtmlTableCell();
HtmlTableCell tableCell4 = new HtmlTableCell();
tableCell1.Attributes.Add("class", "col1");
tableCell2.Attributes.Add("class", "col2");
tableCell3.Attributes.Add("class", "col3");
tableCell4.Attributes.Add("class", "col4");
tableCell1.Controls.Add(_description);
tableCell2.Controls.Add(_cost);
tableCell3.Controls.Add(_heaFunded);
/*if (ShowAddRow || ShowRemoveRow) {
Button addNewButton = new Button();
addNewButton.Text = (ShowAddRow) ? "Add Row" : "Remove";
if (ShowAddRow) {
addNewButton.Click += new EventHandler(addNewButton_Click);
}
if (ShowRemoveRow) {
addNewButton.Click += new EventHandler(removeButton_Click);
}
tableCell4.Controls.Add(addNewButton);
}
else{*/
tableCell4.InnerHtml = " ";
//}
Controls.Add(tableCell1);
Controls.Add(tableCell2);
Controls.Add(tableCell3);
Controls.Add(tableCell4);
}
/*void addNewButton_Click(object sender, EventArgs e) {
if (AddNewRow != null) {
AddNewRow();
}
}*/
/*void removeButton_Click(object sender, EventArgs e) {
if (RemoveNewRow != null) {
RemoveNewRow(this);
}
}*/
protected override void RecreateChildControls() {
EnsureChildControls();
}
public override void RenderBeginTag(HtmlTextWriter writer) {
writer.Write("<tr>");
}
public override void RenderEndTag(HtmlTextWriter writer) {
writer.Write("</tr>");
}
}
应该在Init
创建需要ViewState
并希望接收事件的控件,自定义控件或其他控件。
Http是无状态的。 每次回发都会重新创建整个页面及其所有控件。 您在设计视图中添加的控件将添加到designer.cs文件中,并为您创建。 自己添加控件时,必须编写代码以在以后发生的每个PostBack上重新创建控件。
您可以使用该会话来记住代码添加了哪些控件,并将它们添加到以后的PostBacks中。
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