我有两个条目用户名和密码。用户名和密码始终为大写。我如何强制键盘或输入内容时输入的文本为大写?
<Frame StyleClass="lpframe" x:Name="usernameFrame" CornerRadius="5" BorderColor="Transparent" HasShadow="False">
<StackLayout>
<Label Text="USERNAME" StyleClass="lbl-login">
<Label.FontFamily>
<OnPlatform x:TypeArguments="x:String">
<On Platform="Android" Value="OpenSans-Semibold.ttf#OpenSans-Semibold"/>
</OnPlatform>
</Label.FontFamily>
</Label>
<local:CustomEntry Placeholder="Username" PlaceholderColor="#879baa" Unfocused="entUser_Unfocused" StyleClass="form-control" ReturnType="Next" x:Name="entUser">
<local:CustomEntry.FontFamily>
<OnPlatform x:TypeArguments="x:String">
<On Platform="Android" Value="OpenSans-Regular.ttf#OpenSans-Regular"/>
</OnPlatform>
</local:CustomEntry.FontFamily>
</local:CustomEntry>
</StackLayout>
</Frame>
<Frame StyleClass="lpframe" x:Name="passwordFrame" CornerRadius="5" BorderColor="Transparent" HasShadow="False">
<StackLayout>
<Label Text="PASSWORD" StyleClass="lbl-login">
<Label.FontFamily>
<OnPlatform x:TypeArguments="x:String">
<On Platform="Android" Value="OpenSans-Semibold.ttf#OpenSans-Semibold"/>
</OnPlatform>
</Label.FontFamily>
</Label>
<local:CustomEntry Placeholder="Password" PlaceholderColor="#879baa" Unfocused="entPassword_Unfocused" IsPassword="True" StyleClass="form-control" ReturnType="Go" x:Name="entPassword">
<local:CustomEntry.FontFamily>
<OnPlatform x:TypeArguments="x:String">
<On Platform="Android" Value="OpenSans-Regular.ttf#OpenSans-Regular"/>
</OnPlatform>
</local:CustomEntry.FontFamily>
</local:CustomEntry>
</StackLayout>
</Frame>