entityMap|blocks|key|dml55|text|你的问题有点不清楚，但如果我理解正确的话，当用户更改类别值时，你想触发两个事件吗？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|8llds|通过使用以下语法从主类别方法中显式调用sub方法，您将能够做到这一点|ddrhd|ddlSubCategorySearch_SelectedIndexChanged(sender,e)|code-block|syntax|javascript|4es7h|如果我误解了您的问题，请对其进行修改，使其更清晰一些|cddae|编辑:根据您上面的注释，您不需要调用子ddl的selectedindex更改来更改它的值。|e91a4|您可以从类别下拉列表selectedindexchanged方法中将数据源更改为过滤后的数据源。|ecrr7|我希望这是有意义的|al765^0|0|0|0|0|0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|S|9|@]|A|@]|B|$]]|$2|C|4|D|6|7|8|T|9|@]|A|@]|B|$]]|$2|E|4|F|6|G|8|U|9|@]|A|@]|B|$H|I]]|$2|J|4|K|6|7|8|V|9|@]|A|@]|B|$]]|$2|L|4|M|6|7|8|W|9|@]|A|@]|B|$]]|$2|N|4|O|6|7|8|X|9|@]|A|@]|B|$]]|$2|P|4|Q|6|7|8|Y|9|@]|A|@]|B|$]]|$2|R|4|-4|6|7|8|Z|9|@]|A|@]|B|$]]]]

Your question is a bit unclear but if I understand correctly when the user changes the category value you want to fire both events?

You will be able to do this by explicitly calling the sub method from within the main category method using the following syntax

<pre><code>ddlSubCategorySearch_SelectedIndexChanged(sender,e)
</code></pre>

If I misunderstood your question please edit it to make it a bit more clear

Edit: As per your comment above, you do not need to call the selectedindex change of the sub ddl to change its values.

You can change the datasource to the filtered one from the category dropdowns selectedindexchanged method.

I hope this makes sense

entityMap|blocks|key|2kca8|text|在ddlCategorySearch_SelectedIndexChanged事件上填充ddlSubCategorySearch的DataSource，为此，您首先需要在页面加载时填充ddlCategorySearch的DataSource，如下所示。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4ptee|protected+void++protected+void+Page_Load(object+sender,+EventArgs+e)
{
+++if+(!IsPostBack)
+++{
++++++BindCategorySearch();
++++}+++
}

protected+void+BindCategorySearch()
{
++++//+Fill+your+ddlCategorySearch+here.+Write+down+your+database+logic+to++++
++++//get+a+datasource+for+ddlCategorySearch+
}

protected+void+ddlCategorySearch_SelectedIndexChanged(object+sender,+EventArgs+e)+
{
++++try
++++{
+++++++BindSubCategory();
++++}
++++catch+(Exception+ex)
++++{

++++}
}

protected+void+BindSubCategory()
{
++++try
++++{
+++++++int+categoryID+=+Convert.ToInt32(ddlCategorySearch.SelectedValue);
+++++++//Write+down+here+your+database+logic+to+get+datasource+for+
+++++++//+ddlSubCategorySearch.+For+Example+select+*+from+SubCategory+where+
+++++++//CategoryID+=+categoryID
+++++++List<SubCategory>+listSubcategories+=+new+List<SubCategory>();
+++++++//Fill+your+listCategory+on+base+of+categoryID

+++++++ListItem+li+=+new+ListItem();
+++++++li.Text+=+"--Select+Sub+Category--";
+++++++li.Value+=+"0";
+++++++li.Selected+=+true;
+++++++ddlSubCategories.Items.Insert(0,+li);
++++}
++++catch+(Exception+ex)
++++{

++++}
+}|code-block|syntax|javascript|1qtc1^0|1|12|18|K|1T|A|2K|H|32|A|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|M|9|@$A|N|B|O|C|D]|$A|P|B|Q|C|D]|$A|R|B|S|C|D]|$A|T|B|U|C|D]|$A|V|B|W|C|D]]|E|@]|F|$]]|$2|G|4|H|6|I|8|X|9|@]|E|@]|F|$J|K]]|$2|L|4|-4|6|7|8|Y|9|@]|E|@]|F|$]]]]

Fill your <code>DataSource</code> for <code>ddlSubCategorySearch</code> on <code>ddlCategorySearch_SelectedIndexChanged</code> Event and for that you first need to fill up <code>DataSource</code> for <code>ddlCategorySearch</code> at page Load like following.

<pre><code>protected void protected void Page_Load(object sender, EventArgs e)
{
 if (!IsPostBack)
 {
 BindCategorySearch();
 } 
}

protected void BindCategorySearch()
{
 // Fill your ddlCategorySearch here. Write down your database logic to 
 //get a datasource for ddlCategorySearch 
}

protected void ddlCategorySearch_SelectedIndexChanged(object sender, EventArgs e) 
{
 try
 {
 BindSubCategory();
 }
 catch (Exception ex)
 {

 }
}

protected void BindSubCategory()
{
 try
 {
 int categoryID = Convert.ToInt32(ddlCategorySearch.SelectedValue);
 //Write down here your database logic to get datasource for 
 // ddlSubCategorySearch. For Example select * from SubCategory where 
 //CategoryID = categoryID
 List&lt;SubCategory&gt; listSubcategories = new List&lt;SubCategory&gt;();
 //Fill your listCategory on base of categoryID

 ListItem li = new ListItem();
 li.Text = "--Select Sub Category--";
 li.Value = "0";
 li.Selected = true;
 ddlSubCategories.Items.Insert(0, li);
 }
 catch (Exception ex)
 {

 }
 }
</code></pre>

entityMap|blocks|key|5a7as|text|如果您想根据一个下拉列表填充另一个下拉列表，您可以使用如下命令：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|8o1fd|public+void+ddlCategorySearch_SelectedIndexChanged(object+sender,+Eventargs+e){
var+param+=+ddlCategorySearch.SelectedValue;
foreach+(var+item+in+myList)//assuming+you+put+the+elements+you+want+inside+DDL+in+a+list
if(item.ID+==+param)
ddlSubCategorySearch.Items.Add(new+ListItem+{+Text="",Value=""});+//assign+DDL+elements+here+such+as+item.property
}
}|code-block|syntax|javascript|4mf2m^0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|I|9|@]|A|@]|B|$]]|$2|C|4|D|6|E|8|J|9|@]|A|@]|B|$F|G]]|$2|H|4|-4|6|7|8|K|9|@]|A|@]|B|$]]]]

If you want to populate one dropdown according to the other you can use something like:

<pre><code>public void ddlCategorySearch_SelectedIndexChanged(object sender, Eventargs e){
var param = ddlCategorySearch.SelectedValue;
foreach (var item in myList)//assuming you put the elements you want inside DDL in a list
if(item.ID == param)
ddlSubCategorySearch.Items.Add(new ListItem { Text="",Value=""}); //assign DDL elements here such as item.property
}
}
</code></pre>

entityMap|blocks|key|drdob|text|Remove+second+Dropdown+selected+index+change和auto+postback=false+only+first+dropdown+selected索引更改事件|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4vabg|protected+void++protected+void+Page_Load(object+sender,+EventArgs+e)
++++{
+++++++if+(!IsPostBack)
+++++++{
++++++++++BindCategorySearch();
++++++++}+++
++++}

++++protected+void+BindCategorySearch()
++++{
++++++++//+Fill+your+ddlCategorySearch+here.+Write+down+your+database+logic+to++++
++++++++//get+a+datasource+for+ddlCategorySearch+
++++}

++++protected+void+ddlCategorySearch_SelectedIndexChanged(object+sender,+EventArgs+e)+
++++{
++++++++try
++++++++{
+++++++++++BindSubCategory();
++++++++}
++++++++catch+(Exception+ex)
++++++++{

++++++++}
++++}

++++protected+void+BindSubCategory()
++++{
++++++++try
++++++++{
+++++++++++int+categoryID+=+Convert.ToInt32(ddlCategorySearch.SelectedValue);
+++++++++++//Write+down+here+your+database+logic+to+get+datasource+for+
+++++++++++//+ddlSubCategorySearch.+For+Example+select+*+from+SubCategory+where+
+++++++++++//CategoryID+=+categoryID
+++++++++++List<SubCategory>+listSubcategories+=+new+List<SubCategory>();
+++++++++++//Fill+your+listCategory+on+base+of+categoryID

+++++++++++ListItem+li+=+new+ListItem();
+++++++++++li.Text+=+"--Select+Sub+Category--";
+++++++++++li.Value+=+"0";
+++++++++++li.Selected+=+true;
+++++++++++ddlSubCategories.Items.Insert(0,+li);
++++++++}
++++++++catch+(Exception+ex)
++++++++{

++++++++}
+++++}|code-block|syntax|javascript|8pnc4^0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|I|9|@]|A|@]|B|$]]|$2|C|4|D|6|E|8|J|9|@]|A|@]|B|$F|G]]|$2|H|4|-4|6|7|8|K|9|@]|A|@]|B|$]]]]

Remove second Dropdown selected index change and auto postback=false
 use only first dropdown selectedindex change event

<pre><code>protected void protected void Page_Load(object sender, EventArgs e)
 {
 if (!IsPostBack)
 {
 BindCategorySearch();
 } 
 }

 protected void BindCategorySearch()
 {
 // Fill your ddlCategorySearch here. Write down your database logic to 
 //get a datasource for ddlCategorySearch 
 }

 protected void ddlCategorySearch_SelectedIndexChanged(object sender, EventArgs e) 
 {
 try
 {
 BindSubCategory();
 }
 catch (Exception ex)
 {

 }
 }

 protected void BindSubCategory()
 {
 try
 {
 int categoryID = Convert.ToInt32(ddlCategorySearch.SelectedValue);
 //Write down here your database logic to get datasource for 
 // ddlSubCategorySearch. For Example select * from SubCategory where 
 //CategoryID = categoryID
 List&lt;SubCategory&gt; listSubcategories = new List&lt;SubCategory&gt;();
 //Fill your listCategory on base of categoryID

 ListItem li = new ListItem();
 li.Text = "--Select Sub Category--";
 li.Value = "0";
 li.Selected = true;
 ddlSubCategories.Items.Insert(0, li);
 }
 catch (Exception ex)
 {

 }
 }
</code></pre>

entityMap|blocks|key|3437v|text|你可以为两个DropDowns使用一个函数，检查哪个函数触发了事件，并做相应的事情。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|almi1|protected+void+DualDropDown_SelectedIndexChanged(object+sender,+EventArgs+e)
{
++++DropDownList+dropDownList+=+sender+as+DropDownList;

++++if+(dropDownList.ID+==+"ddlCategorySearch")
++++{
++++++++//do+stuff+if+ddlCategorySearch+fired+the+event
++++}
++++else
++++{
++++++++//do+stuff+if+ddlSubCategorySearch+fired+the+event
++++}
}|code-block|syntax|javascript|3d8m^0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|I|9|@]|A|@]|B|$]]|$2|C|4|D|6|E|8|J|9|@]|A|@]|B|$F|G]]|$2|H|4|-4|6|7|8|K|9|@]|A|@]|B|$]]]]

You can use a single function for both the DropDowns, check which one fired the event and do stuff accordingly.

<pre><code>protected void DualDropDown_SelectedIndexChanged(object sender, EventArgs e)
{
 DropDownList dropDownList = sender as DropDownList;

 if (dropDownList.ID == "ddlCategorySearch")
 {
 //do stuff if ddlCategorySearch fired the event
 }
 else
 {
 //do stuff if ddlSubCategorySearch fired the event
 }
}
</code></pre>

I have this asp <code>DropDownList</code>

<pre><code>&lt;td&gt;
&lt;asp:DropDownList ID="ddlCategorySearch" runat="server" OnSelectedIndexChanged="ddlCategorySearch_SelectedIndexChanged" AutoPostBack="true"&gt;&lt;/asp:DropDownList&gt;&lt;br /&gt;
&lt;asp:DropDownList ID="ddlSubCategorySearch" runat="server" OnSelectedIndexChanged="ddlSubCategorySearch_SelectedIndexChanged" AutoPostBack="true"&gt;&lt;/asp:DropDownList&gt;
</code></pre>



I want to trigger the <code>OnSelectedIndexChanged</code> with two method 
 <code>ddlCategorySearch_SelectedIndexChanged</code> and <code>ddlSubCategorySearch_SelectedIndexChanged</code>

So, if the user triggers the <code>OnSelectedIndexChange</code>, two value method will be triggered. 

But I can't solve that, how can I do that?

ASP.NET C# OnSelectedIndexChanged event trigger multiple Method

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有这个asp DropDownList <td><asp:DropDownList ID="ddlCategorySearch" runat="server" OnSelectedIndexChanged="ddlCategorySearch_SelectedIndexChanged" AutoPostBack="...

问ASP.NET C# OnSelectedIndexChanged事件触发器多方法
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