WPF uses IDataErrorInfo for data validation

This blog will show you how to use IDataErrorInfo for data validation. Take a look at the example below. A customer class, two attributes (FirstName, age)

class customer{    publicstring  FirstName    {        get;         Set ;    }      Public int Age    {        get;         Set ;    }}

Inherit the customer class IDataErrorInfo and implement its properties.

    classCustomer:System.ComponentModel.IDataErrorInfo { Public string  This[stringColumnName] {            Get            {                stringresult =string.                Empty; if(ColumnName = ="FirstName")                {                    if(string. Isnullorwhitespace (FirstName)) {result="Name cannot null or empty."; }                }                Else if(ColumnName = =" Age")                {                    if(Age <0) {result="Age cannot and then zero."; }                }                returnresult; }        }         Public stringError {Get            {                return NULL; }        }         Public stringFirstName {Get; Set; }         Public intAge {Get; Set; }    }

Binds the Firstname,age property of the customer in the UI and triggers validation when the error data occurs.

<Window.Resources> <local:customer x:key="customerinstance"Firstname="Sam Bent"Age=" -"/> <controltemplate x:key="textboxerrortemplate"> <Grid> <border borderbrush="Blue"borderthickness="1"> <AdornedElementPlaceholder/> </Border> </Grid> </ControlTemplate> </Window.Resources> <stackpanel margin="Ten"> <TextBox Text="{BindingSource={StaticResource customerinstance}, Path=FirstName, UpdateSourceTrigger=propertychanged, validatesondataerrors =true} " tooltip="{Binding relativesource={relativesource self}, path= (Validation.errors) [0]. Errorcontent}"  validation.errortemplate="{x:null}"Margin="0,5"/> <textbox text="{BindingSource={StaticResource customerinstance}, Path=Age , UpdateSourceTrigger=propertychanged, validatesondataerrors =true}"            validation.errortemplate="{StaticResource textboxerrortemplate}" ><TextBox.Style> <style targettype="{x:type TextBox}"> <Style.Triggers> <trigger property="Validation.haserror"Value="True"> <setter property="Background"Value="Red"/> <setter property="ToolTip"Value="{Binding Relativesource={relativesource self}, path= (Validation.errors) [0]. Errorcontent}"/> </Trigger> </Style.Triggers> </Style> </TextBox.Style></TextBox> </StackPanel>

The FirstName of the customer is bound to the Age property in two TextBox respectively, and the validatesondataerrors=true is set to trigger the validation. Bind the error message to the ToolTip property of the TextBox,

tooltip= "{Binding relativesource={relativesource self}, path= (validation.errors) [0]. Errorcontent} "or

tooltip= "{Binding relativesource={relativesource self}, path= (validation.errors). Currentitem.errorcontent} " or

<StyleTargetType= "{x:type TextBox}">    <style.triggers>        <Trigger Property= "Validation.haserror"Value= "True">            <Setter Property= "Background"Value= "Red" />            <Setter Property= "ToolTip"Value= "{Binding relativesource={relativesource self}, path= (Validation.errors) [0]. Errorcontent} " />        </Trigger>    </style.triggers></Style>

Errortemplate can also be customized, such as the textboxerrortemplate in the code above.

Operation Result:

Code click here to download, thank you for reading.

WPF uses IDataErrorInfo for data validation