wpf 当DataGrid列模版是ComboBox时，显示信息

​ 实际工作中，有时datagrid控件某一列显示数据是从enum集合里面选择出来的，那这时候设置列模版为combobox就能满足需求。而关于显示的实际内容，直接是enum的string()返回值可能不太适合，这时候采用system.componentmodel.description是一个很好用的方法。

代码中定义的显示类型是enum，实际结果在description中声明。

定义 enum week

    [system.componentmodel.description("星期")]
    public enum week
    {
        [system.componentmodel.description("星期一")]
        monday,

        [system.componentmodel.description("星期二")]
        tuesday,

        [system.componentmodel.description("星期三")]
        wednesday,

        [system.componentmodel.description("星期四")]
        thursday,

        [system.componentmodel.description("星期五")]
        firday,

        [system.componentmodel.description("星期六")]
        saturday,

        [system.componentmodel.description("星期日")]
        sunday,
    }

datagrid模版：

<grid.resources>
    <style x:key="datagridtextcolumnstyle" targettype="{x:type textblock}">
        <setter property="verticalalignment" value="center"/>
        <setter property="horizontalalignment" value="center"/>
    </style>
    
    <style targettype="{x:type datagrid}">
        <setter property="margin" value="0"/>
        <setter property="background" value="#ff8ceb87"/>
        <setter property="autogeneratecolumns" value="false"/>
        <setter property="canuseraddrows" value="false"/>
        <setter property="canuserreordercolumns" value="false"/>
        <setter property="canusersortcolumns" value="false"/>
        <setter property="canuserresizecolumns" value="false"/>
        <setter property="canuserresizerows" value="false"/>
        <setter property="rowheaderwidth" value="30"/>
        <setter property="rowheight" value="30"/>
        <setter property="isreadonly" value="true"/>
        <setter property="cellstyle">
            <setter.value>
                <style targettype="datagridcell">
                    <style.triggers>
                        <trigger property="isselected" value="true">
                            <setter property="background" value="red"/>
                        </trigger>
                    </style.triggers>
                </style>
            </setter.value>
        </setter>
        <setter property="columnheaderstyle">
            <setter.value>
                <style targettype="datagridcolumnheader">
                    <setter property="horizontalcontentalignment" value="center"/>
                </style>
            </setter.value>
        </setter>
    </style>
</grid.resources>

<datagrid itemssource="{binding testdatas}" loadingrow="datagrid_loadingrow" margin="0,0,403.6,10">
    <datagrid.resources>
        <objectdataprovider x:key="weeks" methodname="getnames" objecttype="{x:type sys:enum}">
            <objectdataprovider.methodparameters>
                <x:type typename="local:week"/>
            </objectdataprovider.methodparameters>
        </objectdataprovider>
        
        <local:weekenumtodescriptionconvertor x:key="weekenumtodescription"/>
        <local:weekenumtocomboboxindexconvertor x:key="weekenumtocomboboxindex"/>
    </datagrid.resources>
    
    <datagrid.columns>
        <datagridtemplatecolumn header="week" width ="*">
            <datagridtemplatecolumn.celltemplate>
                <datatemplate>
                    <combobox itemssource="{binding source={staticresource weeks}, converter={staticresource weekenumtodescription}}"
                              selectedindex="{binding testweek, converter={staticresource weekenumtocomboboxindex}, updatesourcetrigger=propertychanged}"/>
                </datatemplate>
            </datagridtemplatecolumn.celltemplate>
        </datagridtemplatecolumn>
        
        <datagridtextcolumn header="message" 
                            binding="{binding testmsg}" 
                            isreadonly="true"
                            elementstyle ="{staticresource datagridtextcolumnstyle}"
                            width ="*"/>
    </datagrid.columns>
</datagrid>

weekenumtodescriptionconvertor、weekenumtocomboboxindexconvertor实现代码：

    class weekenumtocomboboxindexconvertor : system.windows.data.ivalueconverter
    {
        public object convert(object value, type targettype, object parameter, system.globalization.cultureinfo culture)
        {
            return ((int)(week)value);
        }

        public object convertback(object value, type targettype, object parameter, system.globalization.cultureinfo culture)
        {
            return ((week)(int)value);
        }
    }

    class weekenumtodescriptionconvertor : system.windows.data.ivalueconverter
    {
        public object convert(object value, type targettype, object parameter, system.globalization.cultureinfo culture)
        {
            var strvalue = value as string[];
            if (strvalue != null)
            {
                var envalue = new week[strvalue.length];
                for (int i = 0; i < strvalue.length; i++)
                {
                    if (enum.tryparse(strvalue[i], out envalue[i]))
                        strvalue[i] = envalue[i].getdescription();
                }
            }
            return value;
        }

        public object convertback(object value, type targettype, object parameter, system.globalization.cultureinfo culture)
        {
            throw new notimplementedexception();
        }
    }

enumhelper代码：

    public static class enumhelper
    {
        public static string getdescription<t>(this t value) where t : struct
        {
            string result = value.tostring();

            var fi = typeof(t).getfield(result);

            var attributes = (system.componentmodel.descriptionattribute[])fi.getcustomattributes(
                typeof(system.componentmodel.descriptionattribute), true);

            if (attributes != null && attributes.length > 0)
            {
                return attributes[0].description;
            }
            return result;
        }

        public static t getvaluebydescription<t>(this string description) where t : struct
        {
            type type = typeof(t);
            foreach (var field in type.getfields())
            {
                if (field.name == description)
                {
                    return (t)field.getvalue(null);
                }

                var attributes = (system.componentmodel.descriptionattribute[])field.getcustomattributes(
                    typeof(system.componentmodel.descriptionattribute), true);

                if (attributes != null && attributes.length > 0)
                {
                    if (attributes[0].description == description)
                    {
                        return (t)field.getvalue(null);
                    }
                }
            }
            throw new argumentexception(string.format($"{description} 未能找到对应的枚举"), "description");
        }

        public static t getvalue<t>(this string value) where t : struct
        {
            t result;
            if (enum.tryparse(value, true, out result))
            {
                return result;
            }
            throw new argumentexception(string.format($"{value} 未能找到对应的枚举"), "value");
        }

    }

最终效果图

完整代码