/// <summary>
/// Creates a new attribute, optionally based on an existing attribute (and binding) and
/// returns the new attribute after transforming its attribute or binding value.
/// </summary>
/// <param name="attributeName"></param>
/// <param name="original"></param>
/// <param name="transformValue"></param>
/// <returns></returns>
internal static AttributeBinding Transform(string attributeName, AttributeBinding original, Func <string, string> transformValue)
{
var exists = original != null;
var attr = exists ? original.attribute : null;
var result = exists ? original.binding : null;
var bound = result != null;
string value;
if (bound)
{
value = result.Value == null ? "" : result.Value.ToString();
}
else if (exists)
{
value = attr.Value;
}
else
{
value = "";
}
value = transformValue(value);
if (bound)
{
return(new AttributeBinding(new Attribute()
{
Name = attributeName, Value = attr.Value, Binding = attr.Binding
}, new BindingResult()
{
Source = result.Source, Property = result.Property, IsValid = result.IsValid, Value = value
}));
}
else if (!string.IsNullOrEmpty(value))
{
return(new AttributeBinding(new Attribute()
{
Name = attributeName, Value = value
}, null));
}
else
{
return(null);
}
}
protected bool TryRenderIf(AjaxPage page, IEnumerable<string> templateNames, System.IO.TextWriter writer, out AttributeBinding ifBinding, out bool canRender)
{
if (If == null)
{
ifBinding = null;
canRender = true;
return true;
}
ifBinding = If.Evaluate(page);
if (!ifBinding.IsValid)
{
canRender = false;
return false;
}
canRender = JavaScriptHelpers.IsTruthy(ifBinding.Value);
return true;
}
protected bool TryContentTemplate(AjaxPage page, IEnumerable<string> templateNames, System.IO.TextWriter writer, out AttributeBinding contentTemplateBinding)
{
if (ContentTemplate == null)
{
contentTemplateBinding = null;
return true;
}
contentTemplateBinding = ContentTemplate.Evaluate(page);
return contentTemplateBinding.IsValid && contentTemplateBinding.Value is string;
}
internal Constant(string attribute, string expression)
: base(attribute, expression)
{
Extension = null;
Path = null;
binding = new AttributeBinding(new Attribute() { Name = attribute, Value = expression }, null);
}
protected bool TryContentTemplate(AjaxPage page, IEnumerable <string> templateNames, System.IO.TextWriter writer, out AttributeBinding contentTemplateBinding)
{
if (ContentTemplate == null)
{
contentTemplateBinding = null;
return(true);
}
contentTemplateBinding = ContentTemplate.Evaluate(page);
return(contentTemplateBinding.IsValid && contentTemplateBinding.Value is string);
}
protected bool TryRenderIf(AjaxPage page, IEnumerable <string> templateNames, System.IO.TextWriter writer, out AttributeBinding ifBinding, out bool canRender)
{
if (If == null)
{
ifBinding = null;
canRender = true;
return(true);
}
ifBinding = If.Evaluate(page);
if (!ifBinding.IsValid)
{
canRender = false;
return(false);
}
canRender = JavaScriptHelpers.IsTruthy(ifBinding.Value);
return(true);
}
/// <summary>
/// Creates a new attribute, optionally based on an existing attribute (and binding) and
/// returns the new attribute after transforming its attribute or binding value.
/// </summary>
/// <param name="attributeName"></param>
/// <param name="original"></param>
/// <param name="transformValue"></param>
/// <returns></returns>
internal static AttributeBinding Transform(string attributeName, AttributeBinding original, Func<string, string> transformValue)
{
var exists = original != null;
var attr = exists ? original.attribute : null;
var result = exists ? original.binding : null;
var bound = result != null;
string value;
if (bound)
value = result.Value == null ? "" : result.Value.ToString();
else if (exists)
value = attr.Value;
else
value = "";
value = transformValue(value);
if (bound)
return new AttributeBinding(new Attribute() { Name = attributeName, Value = attr.Value, Binding = attr.Binding }, new BindingResult() { Source = result.Source, Property = result.Property, IsValid = result.IsValid, Value = value });
else if (!string.IsNullOrEmpty(value))
return new AttributeBinding(new Attribute() { Name = attributeName, Value = value }, null);
else
return null;
}