Shulou(Shulou.com)06/03 Report--

This article introduces the relevant knowledge of "what is the selective export of Excel solutions from GridView?". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

I. demand analysis

First of all, according to the needs of users, selective export can be carried out. All the exports have been done before, and this new demand has come again, but it is right to think about it carefully. It is not meaningful to export all tens of thousands of pieces of data, but selectively exporting the data that users need is what users need. Where there is a need, there is a solution.

There is more than one solution to any problem, and so is the selective export of GridView. First of all, GridView binds the table data of the database, and we can choose to export. We can also query the required data from the data and obtain the data directly from the foreground GridView table. The question is, how to judge whether the primary key of the selected message (or the whole message) is selected? which direction is more efficient?

II. Solutions

ONE

1. The foreground obtains the primary key information of the selected row, transmits it to the background through JSON format, parses it in the background, and then obtains the data from the database and exports it to Excel through DataTable.

1. Export the selected action

The copy code is as follows:

two。 Foreground JS, the primary key that gets the information of the selected row, that is, GridView must have a column that is the primary key, get all the primary keys and save them in JSON format, and then transfer them to the server

The copy code is as follows:

Function getnumberExport () {

If (ExportCheck ()) {

/ / obtain elements through GridView ID

Var gv = document.getElementById ("ctl00_ContentPlaceHolder1_gridView")

/ / obtain the Input html of GridView

Var mycheck = gv.getElementsByTagName ("input")

/ / define a new array

Var fam = new Array ()

Var hg

Var id

/ / cycle through the checkbox tag to get the primary key information of each piece of data

For (var I = 0; I < mycheck.length; iTunes +) {

If (mycheck.type = = 'checkbox') / / hidden

{

/ / if checkbox is selected

If (mycheck[ I]. Accounts = = true) {

Var numid = new Object ()

Hg = gv.rows (I + 1) .cells (20) [xss_clean]

The / / substring () method is used to extract characters that are mediated between two specified subscripts.

/ / LastIndexOf () reverses the string, fetching the specified character from back to front

Hg = hg.substring (hg.lastIndexOf ("=") + 1, hg.lastIndexOf ("\"))

/ / get the primary key of a piece of data

Id = gv.rows (I + 1) .cells (1) [xss_clean]

Numid.number = hg

Numid.id = id

Fam.push (numid)

}

}

}

/ / $.ajaxSetup ({

/ / async: false / / set to synchronous request

/ /})

/ / convert the array to JSON type

Var nid = JSON.stringify (fam)

/ / post mode to transfer data to the server

$.post ("List.aspx", {Action: "action", numid: nid}, function (result) {

});

}

Else {

Return false

}

}

3. JSON is parsed in the background, converted to DataTable, and exported to Excel

The copy code is as follows:

Protected void Page_Load (object sender, EventArgs e)

{

/ / determine whether the server receives data correctly

If (Request.Params ["Action"]! = null)

{

/ / obtain the JSON of the foreground

String numid = Request.Params ["numid"] .ToString ()

Session ["numid"] = numid

}

}

/ / /

/ / selectively export EXCEL

/ / /

/ / /

/ / /

Protected void Export_Click (object sender, EventArgs e)

{

FamilyPlanningFacade familyPlanningFacade = new FamilyPlanningFacade (); / / instantiate the appearance layer of family planning

DataSet dsAllFamily = new DataSet ()

DataSet dsOneFamily = new DataSet ()

DsAllFamily = familyPlanningFacade.GetAllList (); / / get all the family planning information

DsAllFamily.Tables [0] .Rows.Clear ()

/ / Newtonsoft.Json and Newtonsoft.Json.Linq libraries are required for parsing JSON;

JArray numidget = (JArray) JsonConvert.DeserializeObject (Session ["numid"] .ToString ()

/ / iterate through the required value in JSON, query the database with this value to get a piece of data, and add the data to a new row

For (int I = 0; I < numidget.Count; iTunes +)

{

JObject numberget = (JObject) numidget [I]

String num = numberget ["number"] .ToString ()

If (num.Equals ("))

{

/ / get the key value of id

String id = numberget ["id"] .ToString ()

/ / enBasic.ID = id

/ / query a piece of data through the value of id (unique)

DsExport = famfacade.SelectExport (id)

/ / New Construction Bank

DataRow row = newDataTable.NewRow ()

/ / add data to the new bank

Row.ItemArray = dsExport.Tables [0] .rows [0] .ItemArray

/ / add this line to DataTable

NewDataTable.Rows.Add (row)

}

}

DataTable dtfamilyplanning = new DataTable (); / / create a data table for family planning information

Dtfamilyplanning = newDataTable.Tables [0]

/ / set table field

Dtfamilyplanning = dtfamilyplanning.DefaultView.ToTable (false, new string [] {"ID", "name", "sex"})

/ / modify the header information in order to make the exported Excel header Chinese characters

Dtfamilyplanning.Columns ["ID"] .ColumnName = "number"

Dtfamilyplanning.Columns ["name"] .ColumnName = "name"

Dtfamilyplanning.Columns ["sex"] .ColumnName = "gender"

/ /.... Other information in the table is no longer detailed.

/ / create an object of the DataTableToExcel class

DataTableToExcel dtToExcel = new DataTableToExcel ()

/ / Export data to Excel

DtToExcel.ToExcel (dtfamilyplanning)

}

4. DataTable is exported as an Excel method, which is a good way to stand on the shoulders of giants for my use.

The copy code is as follows:

Public void ToExcel (DataTable dt)

{

DataGrid dgExcel = new DataGrid ()

DgExcel.DataSource = dt

DgExcel.DataBind ()

HttpContext.Current.Response.Charset = "GB2312"

String fileName = HttpUtility.UrlEncode (Guid.NewGuid () .ToString (), System.Text.Encoding.UTF8)

String str = "attachment;filename=" + fileName + ".xls"

HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.UTF8

HttpContext.Current.Response.ContentType = "application/ms-excel"

HttpContext.Current.Response.AppendHeader ("content-disposition", str)

StringWriter sw = new StringWriter ()

HtmlTextWriter htmTextWriter = new HtmlTextWriter (sw)

DgExcel.RenderControl (htmTextWriter)

HttpContext.Current.Response.Write ("")

String style = "td {mso-number-format:\"\ @\ ";}"; / / prevents all-digital data starting with 0 from being removed when excel is exported

HttpContext.Current.Response.Write (style)

HttpContext.Current.Response.Write ("")

HttpContext.Current.Response.Write (sw)

HttpContext.Current.Response.Write ("")

HttpContext.Current.Response.End ()

}

Finally, take a look at the whole implementation of this method:

1 obtain the primary key value of each selected row through the foreground

2 then save all the key values to the array, and convert the array to JSON format

3 is transmitted to the background through AJAX

4 the background receives, parses the JSON, and obtains the value in the JSON

5, you can query the database to get each selected data, and add each row of data to the DataTable

6 is finally exported to Excel.

The problems with this method are as follows: one. The foreground acquires the primary key value of the selected row of the GridView, and obtains the position of the primary key through innerHTML, that is, if the position of the primary key in the HTML changes, the code of the primary key will also change, which has a great impact on the whole body, which has a great impact on the flexibility of the system.

Let's look at the second method:

TWO

2. The background goes directly to the primary key collection of the GridView table in the foreground, and the implementation is similar to the previous method.

1. Export the selected action

The copy code is as follows:

two。 Background button event

The copy code is as follows:

Protected void Export_Click (object sender, EventArgs e)

{

DataSet dsAllFamily = new DataSet ()

DataSet dsOneFamily = new DataSet ()

FamilyPlanningFacade familyPlanningFacade = new FamilyPlanningFacade (); / / instantiate the appearance of family planning

DsAllFamily = familyPlanningFacade.GetAllList (); / / get all the family planning information

DsAllFamily.Tables [0] .Rows.Clear ()

/ / cycle through each line of gridView to find the selected row of CheckBox

Foreach (GridViewRow msgRow in this.gridView.Rows)

{

/ / get the CheckBox you need to traverse through ID

CheckBox chk = (CheckBox) msgRow.FindControl ("DeleteThis")

/ / determine whether CheckBox is selected

If (chk.Checked)

{

/ / get the key value of id

String id = msgRow.Cells [1] .Text.ToString ()

DsOneFamily = familyPlanningFacade.GetList (id)

/ / New Construction Bank

DataRow row = dsAllFaamily.Tables [0] .NewRow ()

/ / add data to the new bank

Row.ItemArray = dsOneFamily.Tables [0] .rows [0] .ItemArray

/ / add this line to DataTable

DsAllFamily.Tables [0] .Rows.Add (row)

}

}

If (dsAllFamily.Tables [0] .Rows.Count = = 0)

{

PersonalFiles.Web.MessageShow.MessageBox.Show (this, "Please select the information you want to export!")

Return

}

DataTable dtfamilyplanning = new DataTable (); / / create a data table for family planning information

Dtfamilyplanning = dsAllFamily.Tables [0]

/ / set table field

Dtfamilyplanning = dtfamilyplanning.DefaultView.ToTable (false, new string [] {"ID", "name", "sex"})

/ / modify the header information in order to make the exported Excel header Chinese characters

Dtfamilyplanning.Columns ["ID"] .ColumnName = "number"

Dtfamilyplanning.Columns ["name"] .ColumnName = "name"

Dtfamilyplanning.Columns ["sex"] .ColumnName = "gender"

/ /.... Other information in the table is no longer detailed.

/ / create an object of the DataTableToExcel class

DataTableToExcel dtToExcel = new DataTableToExcel ()

/ / Export data to Excel

DtToExcel.ToExcel (dtfamilyplanning)

}

The implementation process of this method is very simple. The primary key data displayed by the foreground GridView is obtained directly in the background, which is much simpler than the foreground JSON data.

Three

3. In addition to these two methods, there are faster ways to obtain the displayed data directly from the GridView instead of re-querying the database. The downside is that if the data is operated by many people and updated frequently, then obtaining the data directly from the interface GridView may not be the latest data.

The copy code is as follows:

Protected void Export_Click (object sender, EventArgs e)

{

DataTable dsExport = new DataTable ()

/ / cycle to get each column of gridView and get the header

For (int iTuno Bandi)

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