Selecting or filtering value from DataSet

Suppose we have a District table having fields
District_Key
District_Name
District_StateKey
.....
.....

and have all the values in a dataset

DataSet dsState;

now we want to filter those value whoes state id is 4;
then we we can easily filter those value

DataRow[] dr = dsState.Tables[0].Select("State_Key=4");

Merging cells of a GridView

Suppose that we have a GridView data like this

Main Item	subItem	price
item1	s1	123
item1	s2	456
item 2	s1	878
item2	s2	456
item 2	s3	1231

And we want to create like this

Main Item	sub Item	price
item1	s1	123
	s2	456
item 2	s1	878
	s2	456
	s3	1231

Then we can get it by using the following code

protected void GridView1_DataBound(object sender, EventArgs e)
{
string text = "";
int count = 0;
Hashtable ht = new Hashtable();

// loop through all rows to get row counts
foreach (GridViewRow gvr in GridView1.Rows)
{
if (gvr.RowType == DataControlRowType.DataRow)
{
if (gvr.Cells[0].Text == text)
{
count++;
}
else
{
if (count > 0)
{
ht.Add(text, count);
}
text = gvr.Cells[0].Text;
count = 1;
}
}
}

if (count > 1)
{
ht.Add(text, count);
}


// loop through all rows again to set rowspan
text = "";
foreach (GridViewRow gvr in GridView1.Rows)
{
if (gvr.RowType == DataControlRowType.DataRow)
{
if (gvr.Cells[0].Text == text)
{
gvr.Cells.Remove(gvr.Cells[0]);
}
else
{
text = gvr.Cells[0].Text;
gvr.Cells[0].RowSpan = Convert.ToInt32(ht[text]);
}
}
}
}

To get the number of pixel taken by a string using Graphics in C#

Bitmap myImage;
Graphics g;
myImage = new Bitmap(760, 800, PixelFormat.Format32bppRgb);
g = Graphics.FromImage(myImage);


SizeF size = g.MeasureString("shekhar", new Font("Arial", 8));
int lenght = (int)size.Width;
int height1 = (int)size.Height;

this will give the length and height in pixel of the string "shekhar"

Parent Child Relation between two dropdown in a gridview

To change the drop down value form the other dropdown selected index change.

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
GridViewRow row = (GridViewRow)((sender) as Control).NamingContainer;
DropDownList dr = (DropDownList)sender;
//DropDownList dr = (DropDownList)GridView1.FindControl("DropDownList1");

DropDownList dropdown2 =(DropDownList)row.FindControl("DropDownList2");
string condition = dr.SelectedValue.ToString();
SelectSubCategory(condition,dropdown2);//a function for filling the child gridview
}

GridView Changing the row style

If you want to change the style of row or column of a gridview then it can be done in the following way

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType ==DataControlRowType.DataRow)
{
for (int i = 2; i < e.Row.Cells.Count; i++)
{
e.Row.Cells[i].Style.Add("text-align", "right");
//e.Row.Cells[e.Row.Cells.Count-1].Text = "" + e.Row.Cells[i].Text + "";
}
}
}