blocks|key|170640|text|cbxCategory.SelectedIndex应设置为从0到Items.Count-1的整数，如|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|170641|cbxCategory.SelectedIndex++=+2;|code-block|syntax|javascript|170642|你的|170643|+cbxCategory.SelectedIndex+=+cbxCategory.Items.IndexOf("New")+|170644|只要没有ComboboxItem修改字符串，就应该返回-1+("New")；|170645|尽管我不太喜欢，但另一个解决方案是|170646|foreach(object+obj+in+cbxCategory.Items){+
++++String[2]+objArray+=+(String[])obj+;
++++if(objArray[1]+==+"New"){
+++++++cbxCategory.SelectedItem+=+obj;
+++++++break;+
++++}
}|170647|也许这也需要对您的代码进行以下转换|170648|++++foreach+(string[]+result+in+list)
++++{
++++++cbxCategory.Items.Add(result);
++++}|170649|我还没有测试代码，也不确定转换为String2的情况，但类似的东西应该可以工作|170650|entityMap^0|0|P|U|1|W|D|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1A|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1B|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1C|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1D|8|@]|D|@]|E|$]]|$1|S|3|T|5|H|7|1E|8|@]|D|@]|E|$I|J]]|$1|U|3|V|5|6|7|1F|8|@]|D|@]|E|$]]|$1|W|3|X|5|H|7|1G|8|@]|D|@]|E|$I|J]]|$1|Y|3|Z|5|6|7|1H|8|@]|D|@]|E|$]]|$1|10|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|11|$]]

<code>cbxCategory.SelectedIndex</code> should be set to an integer from <code>0</code> to <code>Items.Count-1</code> like 

<pre><code>cbxCategory.SelectedIndex = 2;
</code></pre>

your 

<pre><code> cbxCategory.SelectedIndex = cbxCategory.Items.IndexOf("New") 
</code></pre>

should return -1 as long as no ComboboxItem mutches the string ("New");

another solution though i don't like it much would be

<pre><code>foreach(object obj in cbxCategory.Items){ 
 String[2] objArray = (String[])obj ;
 if(objArray[1] == "New"){
 cbxCategory.SelectedItem = obj;
 break; 
 }
}
</code></pre>

perhaps this also requires the following transformation to your code

<pre><code> foreach (string[] result in list)
 {
 cbxCategory.Items.Add(result);
 }
</code></pre>

I haven't tested the code and i am not sure about the casting to String[2] but something similar should work

blocks|key|388721|text|看起来您是在cbxCategory.Items集合中搜索字符串，但它包含ComboBoxItem类型的项。因此，搜索将返回-1。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|388722|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

It looks like you're searching the cbxCategory.Items collection for a string, but it contains items of type ComboBoxItem. Therefore the search will return -1.

blocks|key|170717|text|您可以使用LINQ。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|170718|//string+command+=+"SELECT+category_id,+name+FROM+CATEGORY+ORDER+BY+name";
//List<string[]>+list+=+database.Select(command,+false);
//+sample+data...
List<string[]>+list+=+new+List<string[]>+{+new+string[]+{+"aaa",+"bbb"+},+new+string[]+{+"ccc",+"ddd"+}+};

cbxCategory.Items.Clear();

foreach+(string[]+result+in+list)
{
++++cbxCategory.Items.Add(new+ComboBoxItem(result[1],+result[0]));
}

ComboBoxItem+tmp+=+cbxCategory.Items.OfType<ComboBoxItem>().Where(x+=>+x.ResultFirst+==+"bbb").FirstOrDefault();
if+(tmp+!=+null)
++++cbxCategory.SelectedIndex+=+cbxCategory.Items.IndexOf(tmp);|code-block|syntax|javascript|170719|ComboBoxItem类：|offset|length|style|CODE|170720|class+ComboBoxItem
{
++++public+string+ResultFirst+{+get;+set;+}
++++public+string+ResultSecond+{+get;+set;+}

++++public+ComboBoxItem(string+first,+string+second)
++++{
++++++++ResultFirst+=+first;
++++++++ResultSecond+=+second;
++++}
}|170721|entityMap^0|0|0|0|C|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

You can use LINQ.

<pre><code>//string command = "SELECT category_id, name FROM CATEGORY ORDER BY name";
//List&lt;string[]&gt; list = database.Select(command, false);
// sample data...
List&lt;string[]&gt; list = new List&lt;string[]&gt; { new string[] { "aaa", "bbb" }, new string[] { "ccc", "ddd" } };

cbxCategory.Items.Clear();

foreach (string[] result in list)
{
 cbxCategory.Items.Add(new ComboBoxItem(result[1], result[0]));
}

ComboBoxItem tmp = cbxCategory.Items.OfType&lt;ComboBoxItem&gt;().Where(x =&gt; x.ResultFirst == "bbb").FirstOrDefault();
if (tmp != null)
 cbxCategory.SelectedIndex = cbxCategory.Items.IndexOf(tmp);
</code></pre>

<code>ComboBoxItem</code> class:

<pre><code>class ComboBoxItem
{
 public string ResultFirst { get; set; }
 public string ResultSecond { get; set; }

 public ComboBoxItem(string first, string second)
 {
 ResultFirst = first;
 ResultSecond = second;
 }
}
</code></pre>

blocks|key|170749|text|这是我的简单解决方案|type|unstyled|depth|inlineStyleRanges|entityRanges|data|170750|++++++++var+list+=+comboBox1.Items.Cast<string>().ToList();
++++++++cbxCategory.SelectedIndex+=+list.FindIndex(c+=>+c.StartsWith("test"));|code-block|syntax|javascript|170751|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here's my simple solution

<pre><code> var list = comboBox1.Items.Cast&lt;string&gt;().ToList();
 cbxCategory.SelectedIndex = list.FindIndex(c =&gt; c.StartsWith("test"));
</code></pre>

blocks|key|170756|text|我的解决方案是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|170757|int?+defaultID+=+null;
foreach+(DataRow+dr+in+dataSource.Tables["DataTableName"].Rows)
{
+++++if+((dr["Name"]+!=+DBNull.Value)+&&+((string)dr["Name"]+==+"Default+Name"))
+++++{
++++++++++defaultID+=+(int)dr["ID"];
+++++}
}
if+(defaultID+!=+null)+comboBox.SelectedValue+=+defaultID;|code-block|syntax|javascript|170758|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

My solution:

<pre><code>int? defaultID = null;
foreach (DataRow dr in dataSource.Tables["DataTableName"].Rows)
{
 if ((dr["Name"] != DBNull.Value) &amp;&amp; ((string)dr["Name"] == "Default Name"))
 {
 defaultID = (int)dr["ID"];
 }
}
if (defaultID != null) comboBox.SelectedValue = defaultID;
</code></pre>

So I've been looking to set a default value for my combobox. I found a few things but none of them seem to work.

Actually, it works if I create a simple combobox and use <code>comboBox1.SelectedIndex = comboBox1.Items.IndexOf("something")</code> but once I dynamically generate the contents of the comboboxes, I can't get it to work anymore.

This is how I fill my combo box (located in the class's constructor);

<pre><code> string command = "SELECT category_id, name FROM CATEGORY ORDER BY name";
 List&lt;string[]&gt; list = database.Select(command, false);

 cbxCategory.Items.Clear();

 foreach (string[] result in list)
 {
 cbxCategory.Items.Add(new ComboBoxItem(result[1], result[0]));
 }
</code></pre>

I can't seem to get it to work to set a default value, like if I place <code>cbxCategory.SelectedIndex = cbxCategory.Items.IndexOf("New")</code> below the above code, it won't work.

WinForms, by the way.

Thank you in advance.

How to Set default combobox

因此，我一直在寻找为我的组合框设置默认值。我找到了一些东西，但它们似乎都不起作用。实际上，如果我创建一个简单的组合框并使用comboBox1.SelectedIndex = comboBox1.Items.IndexOf("something")，它就可以工作，但是一旦我动态地生成组合框的内容，我就不能再让它工作了。这...

问如何设置默认组合框
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何设置默认组合框EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何设置默认组合框
EN