C# 使用多列过滤数据视图
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Filtering DataView with multiple columns
提问by
In my application I am using a dataview for having the filters to be applied where the filter options are passed dynamically.if there are 2 filter parameters then the dataview should be filtered for parameter1 and then by parameter two. I am using a method which is called in a for loop where I am setting the count to the total no.of parameters selected using a listbox but the filtering is done only for the last parameter. Here is my code:
在我的应用程序中，我使用数据视图来应用过滤器，其中过滤器选项是动态传递的。如果有 2 个过滤器参数，则应针对参数 1 和参数 2 过滤数据视图。我正在使用一种在 for 循环中调用的方法，我将计数设置为使用列表框选择的参数总数，但仅对最后一个参数进行过滤。这是我的代码：
string str = "";
for (int i = 0; i < listbox.Items.Count; i++)
{
if (listbox.Items[i].Selected)
{
if (str != string.Empty)
{
str = str + "," + listbox.Items[i].Text;
}
else
{
str = str + listbox.Items[i].Text;
}
}
}
string[] items = str.Split(',');
for (int i = 0; i < items.Length; i++)
{
ApplyFilter(items[i],dv);
}
private DataView ApplyFilter(string str,DataView newdv)
{
newdv.RowFilter = "[" + str + "]=" + ddl.SelectedItem.ToString();
return newdv;
}
Please provide a suitable solution .
请提供合适的解决方案。
Thanks in advance...
提前致谢...
回答by Canavar
You should apply your filter altogether, not one by one :
你应该完全应用你的过滤器，而不是一个一个：
newdv.RowFilter = "Column1 = " + value1 + " AND Column2 = " + value2;
So you can change your code as :
因此，您可以将代码更改为：
string[] items = str.Split(',');
string filter = string.Empty;
for (int i = 0; i < items.Length; i++)
{
filter += items[i] + " = " + dropdown.SelectedValue;
if (i != items.Length - 1)
{
filter += " AND ";
}
}
newdv.RowFilter = filter;
回答by Tadas ?ukys
I think you should build a complete filter string and then set this filter to your DataView. For example:
我认为您应该构建一个完整的过滤器字符串，然后将此过滤器设置为您的 DataView。例如：
StringBuilder sb = new StringBuilder()
for (int i = 0; i < listbox.Items.Count; i++) {
if (!listbox.Items[i].Selected) {
continue;
}
if (sb.Length > 0) {
sb.Append(" and ");
}
sb.AppendFormat("[{0}] = {1}", listbox.Items[i].Text, ddl.SelectedItem);
}
dv.RowFilter = sb.ToString();
回答by amit poddar
DataView dv = new DataView(dt);
string filterText = "some search criteria";
dv.RowFilter = "Column1 + Column2 + Column3 Like '%" + filterText + "%'";
回答by Fd-ski
I had a similar problem - but i think solution will be the same for both of them. I have a datatable that needs to be filtered by 5 controls and if they aren't filled - it shouldn't be filtered.
我有一个类似的问题 - 但我认为他们两个的解决方案都是一样的。我有一个需要由 5 个控件过滤的数据表，如果它们没有填充 - 它不应该被过滤。
List<string> allParams = new List<string>();
//here add fields you want to filter and their impact on rowview in string form
if (tsPrzelewyTxtOpis.Text != ""){ allParams.Add("Opis like '%" + tsPrzelewyTxtOpis.Text + "%'"); }
if(tsPrzelewyTxtPlatnik.Text != ""){ allParams.Add("P?ac?cy like '%" + tsPrzelewyTxtPlatnik.Text + "%'"); }
if(tsPrzelewyDropDownKonto.Text != "") { allParams.Add("Konto = '" + tsPrzelewyDropDownKonto.Text + "'"); }
if (tsPrzelewyDropDownWaluta.Text != "") { allParams.Add("Waluta = '" + tsPrzelewyDropDownWaluta.Text + "'"); }
if (tsPrzelewyDropDownStatus.Text != "") { allParams.Add("Status = '" + tsPrzelewyDropDownStatus.Text + "'"); }
string finalFilter = string.Join(" and ", allParams);
if (finalFilter != "")
{ (dgvPrzelewy.DataSource as DataTable).DefaultView.RowFilter = "(" + finalFilter + ")"; }
else
{ (dgvPrzelewy.DataSource as DataTable).DefaultView.RowFilter = ""; }
