protected virtual void VisitConstant(ConstantExpression c, SqlVistorFlag flag)
{
var value = c.Value ?? "null";
if (flag.is_right)
{
var paraName = GetCustomParaName(flag.para_pretoken); // flag.GetCustomParaName();
flag.Append(paraName, true);
if (c.Type.IsEnum)
{
AddParameter(paraName, (int)c.Value);
}
else if (c.Type == typeof(bool))
{
AddParameter(paraName, (bool)value ? 1 : 0);
}
else
{
AddParameter(paraName, value);
}
}
else
{
flag.Append(value.ToString());
}
}
private void MethodCallLike(MethodCallExpression exp, SqlVistorFlag flag)
{
Visit(exp.Object, flag);
flag.Append(GetUnaryOperater(flag.unary_type));
flag.Append(" LIKE CONCAT('%',");
VisitRight(exp.Arguments[0], flag);
flag.Append(",'%')");
}
protected virtual void VisitMember(MemberExpression exp, SqlVistorFlag flag)
{
if (exp.Expression != null &&
exp.Expression.NodeType == ExpressionType.Parameter)
{
if (flag.is_right && flag.vistor_type == SqlVistorType.Update)
{
var proParaName = flag.GetParaName(exp.Member.Name);
flag.Append(proParaName, true);
AddMemberProperty(proParaName, exp.Member.Name);
}
else
{
if (exp.Member.DeclaringType.GetTypeInfo().IsGenericType &&
exp.Member.DeclaringType?.GetGenericTypeDefinition() == typeof(Nullable <>))
{
if (exp.Member.Name == "Value")
{
Visit(exp.Expression, flag);
}
if (exp.Member.Name != "HasValue")
{
return;
}
var doesNotEqualNull = Expression.MakeBinary(ExpressionType.NotEqual, exp.Expression,
Expression.Constant(null));
Visit(doesNotEqualNull, flag);
}
else
{
flag.Append(flag.GetColName(exp.Member.Name), true);
}
}
}
else
{
var value = Expression.Lambda(exp).Compile().DynamicInvoke();
Visit(Expression.Constant(value), flag);
}
}
protected virtual void VisitNew(NewExpression nex, SqlVistorFlag flag)
{
for (var i = 0; i < nex.Members.Count; i++)
{
var arg = nex.Arguments[i];
var member = nex.Members[i];
flag.Append(flag.GetColName(member.Name)).Append("=");
VisitRight(arg, flag);
}
}
protected virtual void VisitBinary(BinaryExpression exp, SqlVistorFlag flag)
{
var operand = GetBinaryOperater(exp.NodeType);
if (exp.NodeType == ExpressionType.AndAlso ||
exp.NodeType == ExpressionType.OrElse)
{
flag.Append("(");
Visit(exp.Left, flag);
flag.Append(") ").Append(operand).Append(" (");
Visit(exp.Right, flag);
flag.Append(")");
}
else
{
Visit(exp.Left, flag);
flag.Append(operand);
VisitRight(exp.Right, flag);
}
}