Asp.net updatepanel 清除复选框列表选择
我在 Ajax UpdatePanel 中有一个 ASP.Net CheckBoxList 控件。
我将包含代码 (C#) 以及下面的 HTML。
我发现 CheckBoxList 在回发过程中没有持续存在。
顺便说一句,有点乱。 它是一个原型。
这是用于填充原始 CheckBoxList 的方法
protected void BindCheckboxes()
{
chkBuildings.Items.Clear();
chkNeighborhoods.Items.Clear();
string city = ddlFindHome_Location.SelectedItem.Value.ToLower();
ResidentDataContext rdc = new ResidentDataContext(Utility.Lookup.GetResidentConnectionString());
var neighs = (from n in rdc.spNeighborhoods where n.vchCity.Equals(city) select n);
foreach (var neighborhood in neighs)
{
ListItem li = new ListItem();
li.Value = neighborhood.intNeighborhoodID.ToString();
li.Attributes["onclick"] = string.Format("document.getElementById('{0}').click();", btnNeighHack.ClientID);
li.Text = neighborhood.vchNeighborhood;
chkNeighborhoods.Items.Add(li);
}
var builds = (from b in rdc.spBuildings
join nb in rdc.spNeighborhoodBuildings on b.intBuildingID equals nb.intBuildingID
join n in rdc.spNeighborhoods on nb.intNeightborhoodID equals n.intNeighborhoodID
where n.vchCity.ToLower().Equals(city)
select b).Distinct();
foreach (var buildings in builds)
{
ListItem li = new ListItem();
li.Value = buildings.intBuildingID.ToString();
li.Text = buildings.vchName;
chkBuildings.Items.Add(li);
}
upNeighs.Update();
upBuilds.Update();
}
BindCheckboxes() 调用自:
protected void ddlFindHome_Location_SelectedIndexChanged(object sender, EventArgs e)
{
BindCheckboxes();
}
这是用于填充另一个 CheckBoxList 的复选框的回发方法
protected void btnNeighHack_Click(object sender, EventArgs e)
{
List<int> neighs = new List<int>();
foreach (ListItem li in chkNeighborhoods.Items)
{
if (li.Selected)
neighs.Add(Convert.ToInt32(li.Value));
}
ResidentDataContext rdc = new ResidentDataContext(Utility.Lookup.GetResidentConnectionString());
var builds = (from b in rdc.spBuildings
join nb in rdc.spNeighborhoodBuildings on b.intBuildingID equals nb.intBuildingID
where neighs.Contains(nb.intNeightborhoodID)
select b.intBuildingID).Distinct();
foreach (ListItem li in chkBuildings.Items)
{
li.Selected = false;
}
foreach (ListItem li in chkBuildings.Items)
{
if (builds.Contains(Convert.ToInt32(li.Value)))
li.Selected = true;
}
upBuilds.Update();
}
这是 ASP.Net HTML
<asp:UpdatePanel ID="upNeighs" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<div style="font-weight: bold;">
Neighborhood
</div>
<div style="padding-top: 7px; padding-left: 3px;">
<input type="checkbox" id="chkNeighborhood_CheckAll" />Select All
</div>
<hr />
<div>
<asp:CheckBoxList ID="chkNeighborhoods" runat="server" />
<asp:Button style="display: none;" ID="btnNeighHack" runat="server"
onclick="btnNeighHack_Click" />
</div>
</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdatePanel ID="upBuilds" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<div style="padding-left: 6px; padding-top: 5px; font-weight: bold;">
Building
</div>
<div>
<asp:CheckBoxList ID="chkBuildings" runat="server" />
</div>
</ContentTemplate>
</asp:UpdatePanel>
我应该提到调用了 bindcheckboxes() 函数from
protected void ddlFindHome_Location_SelectedIndexChanged(object sender, EventArgs e)
{
BindCheckboxes();
}
所以它总是一个PostBack。 但我认为你可能对此感兴趣。
I have an ASP.Net CheckBoxList control inside an Ajax UpdatePanel.
I will include the code (C#) along with the HTML below.
I have found that it is something with the CheckBoxList not persisting through the post back.
BTW, it is a little messy. It is a prototype.
This is the method used to populate the original CheckBoxList
protected void BindCheckboxes()
{
chkBuildings.Items.Clear();
chkNeighborhoods.Items.Clear();
string city = ddlFindHome_Location.SelectedItem.Value.ToLower();
ResidentDataContext rdc = new ResidentDataContext(Utility.Lookup.GetResidentConnectionString());
var neighs = (from n in rdc.spNeighborhoods where n.vchCity.Equals(city) select n);
foreach (var neighborhood in neighs)
{
ListItem li = new ListItem();
li.Value = neighborhood.intNeighborhoodID.ToString();
li.Attributes["onclick"] = string.Format("document.getElementById('{0}').click();", btnNeighHack.ClientID);
li.Text = neighborhood.vchNeighborhood;
chkNeighborhoods.Items.Add(li);
}
var builds = (from b in rdc.spBuildings
join nb in rdc.spNeighborhoodBuildings on b.intBuildingID equals nb.intBuildingID
join n in rdc.spNeighborhoods on nb.intNeightborhoodID equals n.intNeighborhoodID
where n.vchCity.ToLower().Equals(city)
select b).Distinct();
foreach (var buildings in builds)
{
ListItem li = new ListItem();
li.Value = buildings.intBuildingID.ToString();
li.Text = buildings.vchName;
chkBuildings.Items.Add(li);
}
upNeighs.Update();
upBuilds.Update();
}
BindCheckboxes() is called from:
protected void ddlFindHome_Location_SelectedIndexChanged(object sender, EventArgs e)
{
BindCheckboxes();
}
This is the post back method for populating the Check Boxes of another CheckBoxList
protected void btnNeighHack_Click(object sender, EventArgs e)
{
List<int> neighs = new List<int>();
foreach (ListItem li in chkNeighborhoods.Items)
{
if (li.Selected)
neighs.Add(Convert.ToInt32(li.Value));
}
ResidentDataContext rdc = new ResidentDataContext(Utility.Lookup.GetResidentConnectionString());
var builds = (from b in rdc.spBuildings
join nb in rdc.spNeighborhoodBuildings on b.intBuildingID equals nb.intBuildingID
where neighs.Contains(nb.intNeightborhoodID)
select b.intBuildingID).Distinct();
foreach (ListItem li in chkBuildings.Items)
{
li.Selected = false;
}
foreach (ListItem li in chkBuildings.Items)
{
if (builds.Contains(Convert.ToInt32(li.Value)))
li.Selected = true;
}
upBuilds.Update();
}
Here is the ASP.Net HTML
<asp:UpdatePanel ID="upNeighs" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<div style="font-weight: bold;">
Neighborhood
</div>
<div style="padding-top: 7px; padding-left: 3px;">
<input type="checkbox" id="chkNeighborhood_CheckAll" />Select All
</div>
<hr />
<div>
<asp:CheckBoxList ID="chkNeighborhoods" runat="server" />
<asp:Button style="display: none;" ID="btnNeighHack" runat="server"
onclick="btnNeighHack_Click" />
</div>
</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdatePanel ID="upBuilds" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<div style="padding-left: 6px; padding-top: 5px; font-weight: bold;">
Building
</div>
<div>
<asp:CheckBoxList ID="chkBuildings" runat="server" />
</div>
</ContentTemplate>
</asp:UpdatePanel>
I should have mentioned that the bindcheckboxes() function is called from
protected void ddlFindHome_Location_SelectedIndexChanged(object sender, EventArgs e)
{
BindCheckboxes();
}
So it is always a PostBack. But I think you might be onto something with that.
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尝试一下。
try that.
好吧,如果您每次更改选择时都清除 CheckBoxList,它也会清除您选择的项目。 我会在 page_load 加载项目。
Well if you clear your CheckBoxList everytime you change a selection, it's gonna clear your selected items too. I would load the items at page_load instead.
经过进一步的研究,我发现控件在回发过程中并未持续存在,并且正在退出视图状态。 因此,每次回发时,都会从以下位置返回一个空对象:
但它发现下拉列表的值不是默认值,并开始重新绑定所有内容。
当我仅在 PostBackControl 是下拉列表时绑定复选框列表时,控件永远不会绑定,因为更新面板中的所有内容都超出了范围。
After further research, I have found that the controls aren't persisting through the post back, and are dropping out of the view state. So each time it posts back, there is a null object returned from:
but it sees that the drop down list's value isn't the default value and starts to rebind everything.
When I only bind the checkbox lists when the PostBackControl is the drop down list, the controls never get bound since everything in the update panel is dropping out of scope.