/// <summary>
/// 执行 <see cref="Expression"/> 的查询，返回查询结果。
/// </summary>
/// <param name="expression">表示 LINQ 查询的表达式树。</param>
/// <returns>单值对象。</returns>
/// <exception cref="TranslateException">对 LINQ 表达式解析失败时抛出此异常。</exception>
public object Execute(Expression expression)
{
var efn = TranslateCache.TryGet(expression, () => (Expression <Func <IDatabase, object> >)GetExecutionPlan(expression));
var func = efn.Compile();
return(func(context.Database));
}
/// <summary>
/// 执行 <see cref="Expression"/> 的查询，返回查询结果。
/// </summary>
/// <param name="expression">表示 LINQ 查询的表达式树。</param>
/// <returns>单值对象。</returns>
/// <exception cref="TranslateException">对 LINQ 表达式解析失败时抛出此异常。</exception>
public object Execute(Expression expression)
{
var efn = TranslateCache.TryGetDelegate(expression, () => (LambdaExpression)GetExecutionPlan(expression));
if (efn.Method.GetParameters().Length == 2)
{
return(efn.DynamicInvoke(service.Database));
}
var segment = SegmentFinder.Find(expression);
return(efn.DynamicInvoke(service.Database, segment));
}
/// <summary>
/// 执行 <see cref="Expression"/> 的查询，返回查询结果。
/// </summary>
/// <param name="expression">表示 LINQ 查询的表达式树。</param>
/// <returns>单值对象。</returns>
/// <exception cref="TranslateException">对 LINQ 表达式解析失败时抛出此异常。</exception>
public object Execute(Expression expression)
{
var efn = TranslateCache.TryGetDelegate(expression, () => (LambdaExpression)GetExecutionPlan(expression));
var attrs = GetMethodAttributes(efn.Method);
if (!attrs.Item2)
{
return(efn.DynamicInvoke(service.Database));
}
var segment = SegmentFinder.Find(expression);
return(efn.DynamicInvoke(service.Database, segment));
}
/// <summary>
/// 执行 <see cref="Expression"/> 的查询，返回查询结果。
/// </summary>
/// <param name="expression">表示 LINQ 查询的表达式树。</param>
/// <returns>单值对象。</returns>
/// <exception cref="TranslateException">对 LINQ 表达式解析失败时抛出此异常。</exception>
public async Task <TResult> ExecuteAsync <TResult>(Expression expression, CancellationToken cancellationToken = default)
{
var efn = TranslateCache.TryGetDelegate(expression, () => (LambdaExpression)GetExecutionPlan(expression));
var attrs = GetMethodAttributes(efn.Method);
object result;
if (attrs.Item1)
{
if (attrs.Item2)
{
var segment = SegmentFinder.Find(expression);
result = efn.DynamicInvoke(service.Database, segment, cancellationToken);
}
else
{
result = efn.DynamicInvoke(service.Database, cancellationToken);
}
}
else
{
if (attrs.Item2)
{
var segment = SegmentFinder.Find(expression);
result = efn.DynamicInvoke(service.Database, segment);
}
else
{
result = efn.DynamicInvoke(service.Database);
}
}
if (result is TResult)
{
return((TResult)result);
}
else if (result is Task <TResult> task)
{
return(task.Result);
}
return(default);