DataGird截取过长字符串代码

【摘 要】 这里需要注意的是DataGrid的Font和Columns[colIndex].ItemStyle.Width属性必需有赋值。如果没有赋值的话，函数将会采用系统默认的值。
　　1.AdjustTextForDisplay(string,int,DataGrid)函数的功能是根据列的宽度，截取过长的字符串；这里需要注意的是DataGrid的Font和Columns[colIndex].ItemStyle.Width属性必需有赋值。如果没有赋值的话，函数将会采用系统默认的值。如不加处理，函数会出异常。
string AdjustTextForDisplay(string text, int colIndex, DataGrid grid)
{
// Calculate the dimensions of the text with the current font
SizeF textSize = MeasureString(text, grid.Font);

// Compare the size with the column's width
int colWidth = (int) grid.Columns[colIndex].ItemStyle.Width.Value;
if(textSize.Width > colWidth)
{
// Get the exceeding pixels
int delta = (int) (textSize.Width - colWidth);

// Calculate the average width of the characters (approx)
int avgCharWidth = (int) (textSize.Width/text.Length);

// Calculate the number of chars to trim to stay in the fixed width (approx)
int chrToTrim = (int) (delta/avgCharWidth);

// Get the proper substring + the ellipsis
// Trim 2 more chars (approx) to make room for the ellipsis
string rawText = text.Substring(0, text.Length-(chrToTrim+2)) + "";

// Format to add a tooltip
string fmt = "{1}";
return String.Format(fmt, text, rawText);
}
return text;
}
　　2.这段代码是处理过长字符串的主体；
void ItemDataBound(object sender, DataGridItemEventArgs e)
{
// Get the string to be displayed
string title = GetTheString();
// Returns the updated text for the specified column
string newText = AdjustTextForDisplay(title, 1, grid);

// Set the text including the tooltip when necessary
e.Item.Cells[1].Text = newText;
}