First of all let´s have a view of GridView control from the Visual Studio Toolbox and put it in the Web Form. The mark up would look something like this:
<asp:gridview ID="Gridview1" runat="server" ShowFooter="true" AutoGenerateColumns="false">
<Columns>
<asp:BoundField DataField="RowNumber" HeaderText="Row Number" />
<asp:TemplateField HeaderText="Header 1">
<ItemTemplate>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Header 2">
<ItemTemplate>
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Header 3">
<ItemTemplate>
<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
</ItemTemplate>
<FooterStyle HorizontalAlign="Right" />
<FooterTemplate>
<asp:Button ID="ButtonAdd" runat="server" Text="Add New Row" />
</FooterTemplate>
</asp:TemplateField>
</Columns>
</asp:gridview>
As this example is intended to generate rows of TextBox in GridView, then we set up some Template Fields columns so that GridView will automatically generates TextBoxes when a new row is being added.
As you can see I have set up a BoundField Column for displaying the Row Number and set up three TemplateField Columns in the Grid and added each column a TextBox Control. You would also notice that I have added a Button Control under the FooterTemplate at the last column in the GridView.
Note:
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Since we are added a Control in the GridView footer, then be sure to set ShowFooter to TRUE in the GridView.
Now let´s switch to the Code behind part of the web form.
As you may know, the GridView control will not show in the page once there is no data associated on it. So the first thing we need here is to set an initial data in the GridView Control. To do this, we can use a DataTable for binding our GridView.
Following is the code block below:
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private void SetInitialRow()
{
DataTable dt = new DataTable();
DataRow dr = null;
dt.Columns.Add(new DataColumn("RowNumber", typeof(string)));
dt.Columns.Add(new DataColumn("Column1", typeof(string)));
dt.Columns.Add(new DataColumn("Column2", typeof(string)));
dt.Columns.Add(new DataColumn("Column3", typeof(string)));
dr = dt.NewRow();
dr["RowNumber"] = 1;
dr["Column1"] = string.Empty;
dr["Column2"] = string.Empty;
dr["Column3"] = string.Empty;
dt.Rows.Add(dr);
//dr = dt.NewRow();
//Store the DataTable in ViewState
ViewState["CurrentTable"] = dt;
Gridview1.DataSource = dt;
Gridview1.DataBind();
}
As you can see, we define four Columns in the DataTable called RowNumber, Column1, Column2 and Column3. The RowNumber column will serve as the key for generating the rows in the GridView. Noticed that for Columns 1, 2 and 3, I assigned an empty value for those columns since the GridView will be generated for the first time. You also noticed that I store the DataTable in ViewState so that we can reference the current data associated within the DataTable when it postbacks.
Now let´s call the method above in Page_Load event:
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protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
SetInitialRow();
}
}
Running the codes above will give us this output below:
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Now create the method for generating the rows when clicking the Button as Follows:
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private void AddNewRowToGrid()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)
{
DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
DataRow drCurrentRow = null;
if (dtCurrentTable.Rows.Count > 0)
{
for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
{
//extract the TextBox values
TextBox box1 = (TextBox)Gridview1.Rows[rowIndex].Cells[1].FindControl("TextBox1");
TextBox box2 = (TextBox)Gridview1.Rows[rowIndex].Cells[2].FindControl("TextBox2");
TextBox box3 = (TextBox)Gridview1.Rows[rowIndex].Cells[3].FindControl("TextBox3");
drCurrentRow = dtCurrentTable.NewRow();
drCurrentRow["RowNumber"] = i + 1;
dtCurrentTable.Rows[i - 1]["Column1"] = box1.Text;
dtCurrentTable.Rows[i - 1]["Column2"] = box2.Text;
dtCurrentTable.Rows[i - 1]["Column3"] = box3.Text;
rowIndex++;
}
dtCurrentTable.Rows.Add(drCurrentRow);
ViewState["CurrentTable"] = dtCurrentTable;
Gridview1.DataSource = dtCurrentTable;
Gridview1.DataBind();
}
}
else
{
Response.Write("ViewState is null");
}
//Set Previous Data on Postbacks
SetPreviousData();
}
As a summary, the code above gets the previous data stored from the ViewState and set the data stored from it into a DataTable so that we can add a new row based from the value entered from the TextBox.
You will also noticed that we call the method SetPreviousData() at the bottom part of the codes above.
Following is the body of SetPreviousData():
----------------------------------------------------------------------------------------
private void SetPreviousData()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)
{
DataTable dt = (DataTable)ViewState["CurrentTable"];
if (dt.Rows.Count > 0)
{
for (int i = 0; i < dt.Rows.Count; i++)
{
TextBox box1 = (TextBox)Gridview1.Rows[rowIndex].Cells[1].FindControl("TextBox1");
TextBox box2 = (TextBox)Gridview1.Rows[rowIndex].Cells[2].FindControl("TextBox2");
TextBox box3 = (TextBox)Gridview1.Rows[rowIndex].Cells[3].FindControl("TextBox3");
box1.Text = dt.Rows[i]["Column1"].ToString();
box2.Text = dt.Rows[i]["Column2"].ToString();
box3.Text = dt.Rows[i]["Column3"].ToString();
rowIndex++;
}
}
}
}
Now, since the methods are all set then we can call this at Button Click event of the Button.
protected void ButtonAdd_Click(object sender, EventArgs e)
{
AddNewRowToGrid();
}
As you can see the code above is very straight forward and self explanatory. Running the code above will give us this output below:
