This post explains how to Remove/Delete Duplicate Rows Records From Datatable using C# or VB.NET in Asp.Net.
My table in database contains duplicate records as shown in image and i want to remove those duplicate records temporaryly efore displaying them in gridview.
For this purpose i'm filling records in DataTable and deleting duplicates.
I have placed one gridview on the page and populating it from DataTable in Page_Load event in code behind.
There are two ways to remove duplicates from datatable.
Method 1:
In this method we create a DataView on DataTable and pass the column names to check for duplicates as array in ToTable method of DataView.
Method 2 :
Create a method which takes datatable and column name to look for duplicates as parameter and returns DataTable after removing duplicate records.
Write this code in Page_Load event of page
And result will be as shown in the image.
All duplicate records have been removed from DataTable.
My table in database contains duplicate records as shown in image and i want to remove those duplicate records temporaryly efore displaying them in gridview.
For this purpose i'm filling records in DataTable and deleting duplicates.
I have placed one gridview on the page and populating it from DataTable in Page_Load event in code behind.
There are two ways to remove duplicates from datatable.
Method 1:
In this method we create a DataView on DataTable and pass the column names to check for duplicates as array in ToTable method of DataView.
C# CODE
DataView dView = new DataView(dtRemoveDuplicate); string[] arrColumns = { "Id", "Name", "Location" }; dtRemoveDuplicate = dView.ToTable(true, arrColumns);
VB.NET CODE
Dim dView As New DataView(dtRemoveDuplicate) Dim arrColumns As String() = {"Id", "Name", "Location"} dtRemoveDuplicate = dView.ToTable(True, arrColumns)
Method 2 :
Create a method which takes datatable and column name to look for duplicates as parameter and returns DataTable after removing duplicate records.
C# CODE
protected DataTable DeleteDuplicateFromDataTable(DataTable dtDuplicate, string columnName) { Hashtable hashT = new Hashtable(); ArrayList arrDuplicate = new ArrayList(); foreach (DataRow row in dtDuplicate.Rows) { if (hashT.Contains(row[columnName])) arrDuplicate.Add(row); else hashT.Add(row[columnName], string.Empty); } foreach (DataRow row in arrDuplicate) dtDuplicate.Rows.Remove(row); return dtDuplicate; }
Write this code in Page_Load event of page
C# CODE
protected void Page_Load(object sender, EventArgs e) { string strConnection = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString; SqlConnection con = new SqlConnection(); con.ConnectionString = strConnection; SqlCommand cmd = new SqlCommand(); cmd.CommandType = CommandType.Text; cmd.CommandText = "SELECT * FROM Details"; cmd.Connection = con; SqlDataAdapter dAdapter = new SqlDataAdapter(cmd); DataTable dtRemoveDuplicate = new DataTable(); dAdapter.Fill(dtRemoveDuplicate); dtRemoveDuplicate = DeleteDuplicateFromDataTable(dtRemoveDuplicate, "Id"); GridView1.DataSource = dtRemoveDuplicate; GridView1.DataBind(); }
VB.NET CODE
Protected Sub Page_Load(sender As Object, e As EventArgs) Dim strConnection As String = ConfigurationManager.ConnectionStrings("ConString").ConnectionString Dim con As New SqlConnection() con.ConnectionString = strConnection Dim cmd As New SqlCommand() cmd.CommandType = CommandType.Text cmd.CommandText = "SELECT * FROM Details" cmd.Connection = con Dim dAdapter As New SqlDataAdapter(cmd) Dim dtRemoveDuplicate As New DataTable() dAdapter.Fill(dtRemoveDuplicate) dtRemoveDuplicate = DeleteDuplicateFromDataTable(dtRemoveDuplicate, "Id") GridView1.DataSource = dtRemoveDuplicate GridView1.DataBind() End Sub Protected Function DeleteDuplicateFromDataTable(dtDuplicate As DataTable, columnName As String) As DataTable Dim hashT As New Hashtable() Dim arrDuplicate As New ArrayList() For Each row As DataRow In dtDuplicate.Rows If hashT.Contains(row(columnName)) Then arrDuplicate.Add(row) Else hashT.Add(row(columnName), String.Empty) End If Next For Each row As DataRow In arrDuplicate dtDuplicate.Rows.Remove(row) Next Return dtDuplicate End Function
And result will be as shown in the image.
All duplicate records have been removed from DataTable.
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2 comments:
very nice code .. thanks for ur help
simple code.
that's very help me.
thank you.
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