How to Perform Edit,Delete,Update Operations in gridview using DataTable and without using Sessions or ViewState

You must elaborate your question firstly.

I guess that you want to implement some operations.
Follow the following codes:

//fulfill datatable
DataTable DT = new DataTable();
DT.Columns.Add("SubjectID", typeof(int));
DT.Columns.Add("School", typeof(string));
DT.Columns.Add("Grade", typeof(string));
DT.Columns.Add("Class", typeof(string));
DT.Columns.Add("Subject", typeof(string));
DT.Columns.Add("Edtion", typeof(string));


//update datatable
DataTable mydt = DT;
DataRow dr = mydt.NewRow();
dr["SubjectID"] = Convert.ToInt32(GridView1.DataKeys[i].Value);
dr["School"] = ddlSchool.SelectedItem.Text;
dr["Grade"] = ddlGrade.SelectedItem.Text;
dr["Class"] = ddlClass.SelectedItem.Text;
dr["Subject"] = GridView1.Rows[i].Cells[3].Text;
dr["Edtion"] = GridView1.Rows[i].Cells[4].Text;
mydt.Rows.Add(dr);

GridView2.DataSource = mydt;
GridView2.DataBind();

//delete
protected void GridView2_RowCommand(object sender, GridViewCommandEventArgs e)
{
int gvindex = Convert.ToInt32(e.CommandArgument);//get gridview index

DataTable mydt = DT;
try
{
DataRow[] drs = mydt.Select("SubjectID=" + GridView2.DataKeys[gvindex].Value.ToString());
foreach (DataRow dr in drs)
{
dr.Delete();
}

}
catch(Exception ex)
{
throw ex;
}
GridView2.DataSource=mydt;
GridView2.DataBind();
}

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