public static WhereClause CreateWhereClause <TObject>(Expression <Func <TObject, bool> > expr) where TObject : DataObject
{
var visitor = new LinqVisitor();
visitor.Visit(expr);
return(visitor.GeneratedExpression);
}
protected override Expression VisitBinary(BinaryExpression node)
{
switch (node.NodeType)
{
case ExpressionType.AndAlso:
Visit(node.Left);
Visit(node.Right);
return(node);
case ExpressionType.OrElse:
var visitor = new LinqVisitor();
visitor.Visit(node.Left);
visitor.Visit(node.Right);
Expressions.Add(visitor.Expressions.First().Or(visitor.Expressions.Last()));
return(node);
}
string sqlOp;
if (!ExpressionTypeToSqlOperator.TryGetValue(node.NodeType, out sqlOp))
{
return(node);
}
var value = GetValue(node.Right);
if (value == null && node.NodeType == ExpressionType.Equal)
{
Expressions.Add(DB.Column(GetColumnName(node.Left)).IsNull());
}
else if (value == null && node.NodeType == ExpressionType.NotEqual)
{
Expressions.Add(DB.Column(GetColumnName(node.Left)).IsNotNull());
}
else
{
Expressions.Add(new FilterExpression(GetColumnName(node.Left), sqlOp, value));
}
return(node);
}
public IDbOper <T> Where(Expression <Func <T, bool> > sl)
{
List <object> tp = null; var dc = Fields;
using (var tp1 = new LinqVisitor())
{
tp = tp1.Visit(sl) as List <object>;
StringBuilder sb = new StringBuilder(); string s = string.Empty;
var a = ps.Count;
for (int i = 0; i < tp.Count; i += 4)
{
s = db.ParStr("Par" + (a + i));// db.ParStr(tp[i].ToString());
sb.Append(Quote(tp[i].ToString()) + tp[i + 1].ToString() + s);
if (i + 4 < tp.Count)
{
sb.Append(tp[i + 3]);
}
ps.Add(db.Cp(s, tp[i + 2]));
}
Where(sb.ToString());
}
return(this);
}