The Validate tag whose type is set to "xml" is referred to as an XML Validator and is used to ensure the user provides a well-formed XML snippet as input for a given control. NOTE: that this provides very basic verification the XML is well-formed. Deeper checks are not performed.
<Validate
BackColor="color name|#dddddd"
BorderColor="color name|#dddddd"
BorderStyle="NotSet|None|Dotted|Dashed|Solid|Double|Groove|Ridge| Inset|Outset"
BorderWidth="size"
CssClass="string"
Display="Static|Dynamic"
EnableClientScript="True|False"
Font-Bold="True|False"
Font-Italic="True|False"
Font-Names="string"
Font-Overline="True|False"
Font-Size="string|Smaller|Larger|XX-Small|X-Small|Small|Medium| Large|X-Large|XX-Large"
Font-Strikeout="True|False"
Font-Underline="True|False"
ForeColor="color name|#dddddd"
Height="size"
Message="string"
Target="string"
Text="string"
Type="XML"
Width="size" />
The XML validator is one type of the <validate> tag. When the "type" attribute is set to xml, the control prevents the form from being submitted if its associated control does not contain well-formed XML. You associate a control with the <validate> tag by setting its "target" attribute to the ID of the control you wish to validate. The "message" attribute is the text that will be displayed to the user when validation fails. If you are using the <validationsummary> tag, then you can also supply a "text" attribute. When validation fails, the "text" will be displayed where your <validate> tag is and the "message" will be displayed in the <validationsummary>. The "display" attribute determines if the the <validate> tag will reserve space for its message in the page layout - typically resulting in blank space in your form -or whether it will dynamically display allocate the space for the message when validation fails. The <validate> tag defaults to Dynamic display.
<addform> <submitcommand commandtext="INSERT INTO Users(FirstName,
LastName, MyXml) VALUES(@FirstName, @LastName, @MyXml)" /> <table> <tr>
<td>
<label for="txtFirstName" text="FirstName" /> <textbox id="txtFirstName" datafield="FirstName"
datatype="string" />
</td> </tr> <tr>
<td>
<label for="txtLastName" text="Last Name" /> <textbox id="txtLastName" datafield="LastName"
datatype="string" />
</td> </tr> <tr>
<td>
<label for="txtXml" text="Your XML" /> <textarea id="txtXml" datafield="MyXml"
datatype="string" /> <validate type="xml" target="txtXml" message="Please enter well-formed XML" />
</td> </tr> <tr>
<td colspan="2">
<addbutton text="Add"/> <cancelbutton
text="Cancel"/>
</td> </tr> </table> </addform>