Easy QueryBuilder - A User-Friendly Ad-Hoc Advanced Search Solution
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by Bing Wang
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A User Control

In this web project, the query builder was designed as a user control that can be called from several parent pages such as Search Person, Search Platform, and Search ID. The figure below shows the design form of query builder and data grid. The query builder consists of four key elements: T-SQL operator (e.g., AND), query attribute which is dynamically read from tables (e.g., Last Name), query operator (e.g., Begins With), and the HTML control which are based on the attribute data types (e.g., text boxes, list boxes or calendar controls).

Web Form with AJAX

With the implementation of AJAX, only changes are updated on the web form.  Other sections remain unchanged. This avoids unnecessary full page reloading.

Event Code

Users can easily compose the query context such as adding queries to filter list, deleting query item, or navigating the filter through the list. Update panel makes sure only the list box is posted back. See the C# code snippets:

Listing 1 - Add List Item

protected void btnAddFilter_OnClick(object sender, EventArgs e)
    {
        string filterText = "", filterValue = "", filterTextValue = "";
        if (lstCriteria.Items.Count > 0)
        {
            filterText = ddlANDOR.SelectedItem.Text + " ";
            filterValue = ddlANDOR.SelectedItem.Text + ";";
            filterTextValue = ddlANDOR.SelectedItem.Text + ";";
        }
        filterText += ddlCols.SelectedItem.Text + " ";
        filterTextValue += ddlCols.SelectedItem.Text + ";";
        filterValue += ddlCols.SelectedValue + ";";
        filterText += ddlOperator.SelectedValue + " ";
        filterValue += ddlOperator.SelectedValue + ";";
        filterTextValue += ddlOperator.SelectedValue + ";";
        filterText += txtCriteria.Text.Trim();
        filterTextValue += txtCriteria.Text.Trim();
        filterValue += txtCriteria.Text.Trim();
        lstCriteria.Items.Add(new ListItem(filterText, filterTextValue + 
            "|" + filterValue));
        upCriteria.Update();
  }

Listing 2 - Delete List Item

protected void btnRemove_OnClick(object sender, EventArgs e)
    {
        if ((lstCriteria.SelectedIndex == 0) && (lstCriteria.Items.Count > 1))
        {
            ListItem item = lstCriteria.Items[1];
            int idx = item.Text.IndexOf(' ');
            string strAndOr = item.Text.Substring(0, idx);
            string[] itemValues = item.Value.Split("|".ToCharArray());
            string filterTextValue = itemValues[0].Substring(idx + 1,
                  itemValues[0].Length - idx - 1);
            string filterValue = itemValues[1].Substring(idx + 1, 
                  itemValues[1].Length - idx - 1);
            item.Text = item.Text.Substring(idx + 1, item.Text.Length - idx - 1);
            item.Value = filterTextValue + "|" + filterValue;
        }
        lstCriteria.Items.RemoveAt(lstCriteria.SelectedIndex);
    }

Listing 3 - Move Up List Item

protected void btnUp_OnClick(object sender, EventArgs e)
    {
        if (lstCriteria.SelectedIndex == 1)
        {
            ListItem item = lstCriteria.SelectedItem;
            ItemMove(item);
        }
        if (lstCriteria.SelectedIndex > 0)
        {
            int idxSelected = lstCriteria.SelectedIndex;
            int idxOther = idxSelected - 1;
            lstCriteria.Items.Insert(idxSelected + 1, 
                  lstCriteria.Items[idxOther]);
            lstCriteria.Items.RemoveAt(idxOther);
        }
    }

Listing 4 - Move Down List Item

protected void btnDown_OnClick(object sender, EventArgs e)
    {
        if ((lstCriteria.SelectedIndex == 0) && (lstCriteria.Items.Count > 1))
        {
            ListItem item = lstCriteria.Items[1];
            ItemMove(item);
        }
        if (lstCriteria.SelectedIndex < lstCriteria.Items.Count - 1)
        {
            int idxSelected = lstCriteria.SelectedIndex;
            int idxOther = idxSelected + 1;
            lstCriteria.Items.Insert(idxSelected, lstCriteria.Items[idxOther]);
            lstCriteria.Items.RemoveAt(idxOther + 1);
        }
    }

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